Import milestones from GitHub

Closes #13421

See merge request !3797

Import labels from GitHub

Closes #15292

See merge request !3776

Use GitHub Issue/PR number as iid to keep references

Closes #15294 

See merge request !3759

Fixed issue with multi select not working with arrow keys



See merge request !3792

Add null check to formData.append

Fixes https://gitlab.com/gitlab-com/support-forum/issues/645

See merge request !3799

Change the link color of the target branch in a merge rquest

closes #15296

See merge request !3786

Use raw SQL commands for 20140502125220 MigrateRepoSize

Partial fix for #15210

See merge request !3789

Fixed overlap in header on mobile

![Screen_Shot_2016-04-18_at_08.48.29](/uploads/8f371d0c717a57ca7afb29415e13d96c/Screen_Shot_2016-04-18_at_08.48.29.png)

See merge request !3777

Removes dropzone focus class after dropping file



See merge request !3756

Updated note form focus to better match form-control focus

![Screen_Shot_2016-04-15_at_09.47.52](/uploads/39e02f79a72798ecc6dc946c7b3c8e2e/Screen_Shot_2016-04-15_at_09.47.52.png)

See merge request !3739

Wrap code in parallel view

Code scrolling was breaking the parallel layout. It should wrap on 'Side-by-side' mode

<img src="/uploads/db657e6c7f08ce57f1be615d7193136a/Screen_Shot_2016-04-14_at_4.28.31_PM.png" width="700px">

See merge request !3731

Fixed issue with commit time not using timeago



See merge request !3723

Partial fix for #15210

Fixed issue with spinner not hiding on diff changes

See merge request !3793

Add "action" tag to /internal/allowed API

See merge request !3791

This allows us to re-use any other analytics that rely on the "action"
tag having a value set.

Restrict public users for private instances

Implements #3508

See merge request !3440

With these changes we don’t lost the issue/pr references when importing
them to GitLab.

Count the number of SQL queries per transaction

cc @pcarranza 

See merge request !3783