Migrate from Sidetiq to Sidekiq-cron EE specific jobs

This is a followup from gitlab-org/gitlab-ce#2355 with specific EE jobs migrated to use Sidekiq-cron instead of Sidetiq

See merge request !69

Updated Sidekiq to 3.5.x

CE upstream

@dzaporozhets Please resolve these conflicts
```
Unmerged paths:
  (use "git add <file>..." to mark resolution)

	both modified:   app/views/groups/group_members/index.html.haml
	both modified:   app/views/projects/project_members/index.html.haml
```

See merge request !67

Improve reliability of LdapSyncWorker

First of all, Sidekiq job retries are not needed because this is a
recurring job. Second of all, we add the option to run once every
X days instead of once every day. This helps when the job takes
close to or more than 24 hours to complete.

See merge request !68

Fix failures in master



See merge request !1974

Git rid of deprecated warnings after rails update

https://gitlab.com/gitlab-org/gitlab-ce/issues/3798

https://gitlab.com/gitlab-org/gitlab-ce/issues/3797

See merge request !1946

Fix broken spec related to MySQL and fractional seconds support.



See merge request !1973

UI: Improve consistency across the board

Depends on !1953

See the commits for more details, the messages mostly speak for themselves.

Fixes https://dev.gitlab.org/gitlab/gitlabhq/issues/2577

See merge request !1954

UI: Remove minimum container height

Depends on !1953

See the commits for more details, the messages mostly speak for themselves.

Before:

![Screen_Shot_2015-12-02_at_15.42.07](/uploads/1d8e19e4738bec39074cbb9afc400ad5/Screen_Shot_2015-12-02_at_15.42.07.png)

After:

![Screen_Shot_2015-12-02_at_15.50.34](/uploads/56153fe19bb72163a2dc9dd83850ad89/Screen_Shot_2015-12-02_at_15.50.34.png)


See merge request !1957

UI: More consistent alignment and padding

See the commits for more details, the messages mostly speak for themselves.

# Highlights:

## Merge request form bottom

Before:

![mr_before](/uploads/de2ae608d300784b61818bc33538ac64/mr_before.png)

After: 

![mr_after](/uploads/9b1568d8287704ee9497cc029e827778/mr_after.png)

## Issue header

Before:

![issue_before](/uploads/e8cc4fb316219f025ff7bd74c7da8677/issue_before.png)

After:

![issue_after](/uploads/5fbad99f038571196c3c3c2bea304381/issue_after.png)

## Empty repository message

Before:

![empty_before](/uploads/f6ab80aea9af9111c3dc260d5fa98cd6/empty_before.png)

After:

![empty_after](/uploads/40a528f5a45f4e47776356c88aab24c4/empty_after.png)

Fixes #3742 and https://dev.gitlab.org/gitlab/gitlabhq/issues/2594

See merge request !1953

Also update gitlab-workhorse in patch updates [ci skip]

Fixes #3747 

See merge request !1959

Prevent impersonation if blocked

First of all, Sidekiq job retries are not needed because this is a
recurring job. Second of all, we add the option to run once every
X days instead of once every day. This helps when the job takes
close to or more than 24 hours to complete.

fixed the documentation of the Guest role in permission.md

This MR fixes the documentation of the Guest role.  

closes gitlab-org/gitlab-ce#3777 

cc @dblessing @JobV 

See merge request !1952