Added update guide for 8.11

## What does this MR do?

I need to add notes about Elastic on EE side. To not create ugly conflicts in the future and to not duplicate work I created it here first.

I followed this guide https://gitlab.com/gitlab-org/release-tools/blob/master/doc/release-candidates.md#gitlab-ce

See merge request !5545

Replace reject_blocked with reject_blocked! in skipped callbacks.

`reject_blocked!` was introduced in c9def945, I can't find any references to `reject_blocked` ever existing.

See merge request !5532

In Rails 4.2 and below, skipping callbacks (skip_before_action, skip_after_action, etc.) that use methods which do not exist will not throw any errors.

On the other hand, Rails 5 does. See https://github.com/rails/rails/pull/19029

After testing with Rails 5 I noticed there are some methods that don't actually exist (because they were renamed, usually), this fixes a few instances of those.

reject_blocked! was introduced in c9def945, I can't find any references to reject_blocked ever existing.

Submit new issues created via the WebUI or API to Akismet for spam check on public projects.

## What does this MR do?

Submit new issues created via the WebUI by non project members to Akismet for spam check.

## Why was this MR needed?

Support for Akismet was added only to the API with !2266. This MR builds on that functionality to also check issues submitted via the WebUI for spam.

## What are the relevant issue numbers?

Related to:

- #5573 
- #5932 
- gitlab-com/infrastructure#14
- gitlab-com/support#61
- !2266

cc @stanhu @MrChrisW 

See merge request !5333

Update attr_encrypted from 3.0.1 to 3.0.2

This removes methods that were deprecated by Rails 5 so we won't have as many deprecation warnings when we update to Rails 5. Working toward #14286.

Changelog: https://github.com/attr-encrypted/attr_encrypted/blob/master/CHANGELOG.md#302

See merge request !5438

Update rack-oauth2 from 1.2.1 to 1.2.3.

Removes methods deprecated in Rails 5. Working toward #14286.

Changelog: https://github.com/nov/rack-oauth2/compare/v1.2.1...v1.2.3

See merge request !5439

Upgrade Bullet from 5.0.0 to 5.2.0

Removes methods that were deprecated in Rails 5. Working toward #14286.

Changelog: https://github.com/flyerhzm/bullet/blob/master/CHANGELOG.md#520-07262016

See merge request !5443

Upgrade gon from 6.0.1 to 6.1.0.

Removes methods that were deprecated in Rails 5. Working toward #14286.

Changelog: https://github.com/gazay/gon/compare/3a2b56d...9d89bc9

See merge request !5442

Upgrade default_value_for from 3.0.1 to 3.0.2.

Includes support for Rails 5. Working toward #14286.

Changelog: https://github.com/FooBarWidget/default_value_for/compare/release-3.0.1...release-3.0.2

See merge request !5441

Fix renaming repository when name contains invalid chars under settings

Fixes #19538

See merge request !5490

Generate coverage report from whole test suite

Extends our CI plan to merge all coverage results and generate HTML report.

See merge request !5018

Allow skipping users in autocomplete

Ref: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/560

See merge request !5471

Resolve "HipChat notifications missing colors"

_Originally opened at !2322 by @eisnerd._

- - -

## What does this MR do?

This MR restores the colors mentioned in #5571 by overriding the color setting with green/red just for build events.

## What are the relevant issue numbers?

Closes #5571.

See merge request !5498

Make error pages responsive

## What does this MR do?

This MR makes error pages responsive design and all users have better experiences on 404/422/500/502/503/in-deploy error.

## Are there points in the code the reviewer needs to double check?

n/a

## Why was this MR needed?

404/422/500/502/503/in-deploy error pages were designed only for PC and not good for mobile users.

## What are the relevant issue numbers?

Closes #19345

## Screenshots (if relevant)

### PC
![improved-404-lg-v3](/uploads/280f48f95bd446888a81cc2150877cd8/improved-404-lg-v3.png)

### mobile

(with `max-width: 40vw` for `img` (@connorshea) and `max-width: 800px` for `hr` (@annabeldunstone) )
![improved-404-xs-v3](/uploads/9764aac3992dedb6b437045943a07fe5/improved-404-xs-v3.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5000

Pass an array of user IDs in the `skip_users` param to have them
excluded from the results (unless they are explicitly included through
the `current_user` or `author_id` params).

[ci skip]
Signed-off-by: Rémy Coutable <remy@rymai.me>

CE upstream

@iamphill All these conflicts are frontend related, could you resolve/reassign them?
```
Unmerged paths:
  (use "git add <file>..." to mark resolution)

	both added:      app/assets/javascripts/application.js
	both added:      app/assets/javascripts/confirm_danger_modal.js
	both added:      app/assets/javascripts/dispatcher.js
	both added:      app/assets/javascripts/groups_select.js
	both added:      app/assets/javascripts/lib/utils/common_utils.js
	both added:      app/assets/javascripts/merge_request_widget.js
	both added:      app/assets/javascripts/notes.js
	both added:      app/assets/javascripts/project_new.js
	both added:      app/assets/javascripts/users_select.js
	both modified:   app/views/projects/branches/index.html.haml
```

See merge request !595

Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

Resolve "Empty project page does not show Repository section on navbar after creating first branch/file"

This MR aims to fix the rendering of the project's page after creating a README/LICENSE/.gitignore and creating the first branch of the project on the website.
Pictures related with the problem this MR fixes linked in #20025

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

Closes #20025

See merge request !5399

Project and branch cache is expired when project is still
empty or new branch is created. develops tests accordingly
Signed-off-by: Rémy Coutable <remy@rymai.me>

Optimize maximum user access level lookup in loading of notes

See merge request !5412

Resolve "Remove routes that we do not use anymore"

_Originally opened at !4059 by @strzibny._

- - -

## What does this MR do?

> I tried to clean up the routes as mentioned in #14584
I used the following script and manually verified the changes: https://gist.github.com/strzibny/4ccbda7dcf67ef6719dcb047014e1ea7
After this patch, the script still gives me the following routes:
Unused routes (7): oauth/authorizations#show doorkeeper/tokens#create doorkeeper/tokens#revoke oauth/applications#edit oauth/applications#show doorkeeper/token_info#show omniauth_callbacks#(?-mix:(?!))
Here is a relevant code from doorkeeper on drawing these routes: https://github.com/doorkeeper-gem/doorkeeper/blob/5ea4575863781940fe6996692c6b41f2ad71d90e/lib/doorkeeper/rails/routes.rb#L25

## What are the relevant issue numbers?

Closes #14584.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)


See merge request !5499

Signed-off-by: Rémy Coutable <remy@rymai.me>

Update gitlab-shell version to 3.2.1 in the 8.9->8.10 update guide

## What does this MR do?

Update gitlab-shell version to 3.2.1 in the 8.9->8.10 update guide (missing from gitlab-org/gitlab-ce!5509).

See merge request !5516

Fix broken user_allowed check in Git Annex push

https://gitlab.com/gitlab-org/gitlab-ee/commit/3e4934cea6e2909fe978e5e38a659e4e6f818430 seems to have moved`user_allowed` into the `UserAccess` class, but since no specs tested `git_annex_access_check` a push from Git Annex would fail with an undefined method.

Closes #816

See merge request !597

Signed-off-by: Rémy Coutable <remy@rymai.me>

This was missing from gitlab-org/gitlab-ce!5509.
Signed-off-by: Rémy Coutable <remy@rymai.me>