Fixed issue with group name not showing

Fixed spacing with buttons
Disables group form when user doesnt have correct permissions

Hides time on mobile

Added group name to members row
Fixed saving group member

Combine both group members & project members in project members list

Include region in S3 configuration

- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)

See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5336

See merge request !5896

Ensure specs on sorting of issues in API are deterministic on MySQL

## What does this MR do?

Ensure a deterministic order of issues on the existing API issues specs

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

## Why was this MR needed?

To avoid random failures as described on #22057

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- ~~[ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- ~~[ ] API support added~~
- Tests
  - ~~[ ] Added for this feature/bug~~
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [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)

## What are the relevant issue numbers?

Closes #22057

See merge request !6306

Fix two problematic bits of code that will be deprecated or broken in Rails 5.

Found in the Rails 5 MR: !5555

These are safe to use in Rails 4.2.7 as well as Rails 5.0.0, so I figured I'd backport them for the sake of making that merge request smaller.

The explanation for the mime_types.rb code is here: https://github.com/rails-api/active_model_serializers/issues/1027#issuecomment-126543577

See merge request !6214

Update templates.

See merge request !6163

Only add original author tag line when importing from GitHub if there isn't a linked GitLab account

## What does this MR do?
If there we've found a linked GitLab user for a creator of an issue or comment don't add the 'Created By:' line.

## What are the relevant issue numbers?

Closes #21569

See merge request !6081

Document how to track custom events

## What does this MR do?

This documents how one can track custom events.

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

Spelling, etc.

## Why was this MR needed?

This wasn't documented.

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] 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)

## What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/22070

See merge request !6310