Milestone drag & drop cursor
Fixes#4097

cc @jschatz1 @creamzy
See merge request !2532
Added cache:key to .gitlab-ci.yml allowing to fine tune the caching
The `cache:key` allows you to define the affinity mask of caching, allowing to have single cache for all jobs, or cache per-job, or per-branch, or any other way you would need:
1. Cache per-build for all branches:
```
cache:
key: "$CI_BUILD_NAME"
untracked: true
```
2. Cache per-branch for all jobs:
```
cache:
key: "$CI_BUILD_REF"
untracked: true
```
/cc @DouweM @grzesiek @axil
See merge request !2436
Implement new UI for pagination
Fixes#6063 
See merge request !2517
Creator should be added as a master of the project on creation
Fixes#4222
This also enable a project creator to add themselves as a master of the
project for existing repositories that were created in the meanwhile
that they don't appear as members.
See merge request !2520
Adds disabled comment field and disabled avatar.
Fixes#3540

See merge request !2508
Added documentation for GitLab Metrics
This adds documentation for the metrics code I recently added.
Two notes:
* I'm referring to this feature as "GitLab Metrics" everywhere simply
because the code resides in the `Gitlab::Metrics` namespace. A
different name is fine, though I think just "Metrics" might be a bit
too abstract.
* Grafana isn't covered since it's fairly straight-forward to setup
(there's nothing really special we can cover). I think we _should_
cover it once we start shipping it with Omnibus.
I assigned @axil since he's our technical writer/documentation guru,
feel free to re-assign if needed.
cc @sytses @axil @dzaporozhets @JobV
See merge request !2484
Add note about minimum GitLab CI version
Documentation update: To use variables in `.gitlab-ci.yml` it's not enough to update the GitLab Runner, a minimum version of GitLab CI is needed as well.
See merge request !2514
Add sentry integration
Sentry is an event logging platform primarily focused on capturing and
aggregating exceptions. With this MR it will be possible to log and
track exceptions from GitLab to Sentry.
https://gitlab.com/gitlab-com/operations/issues/39
See merge request !2485