Throttle the update of `project.last_activity_at` to 1 minute

This implement [the solution](https://gitlab.com/gitlab-org/gitlab-ce/issues/15094#note_4769387) proposed by @jacobvosmaer.

See merge request !3848

Upgrade gitlab-grit gem to 2.8.1, loosening the mime-types gem's version dependency.

Changelog for mime-types: https://github.com/mime-types/ruby-mime-types/blob/master/History.rdoc

Resolves #15101.

See merge request !3901

Link user avatar in activity page to user profile

Closes #14927

See merge request !3910

Move CHANGELOG entry to 8.8

Fixes CHANGELOG entry for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3686

See merge request !3914

Fixes issue with emoji comments not showing correct emoji image

Previously it would look for the unicode character inside the award menu. But this menu might not always be there.

Now, the unicode characters are loaded onto the page in an array which the award emoji that looks in to get the correct emoji unicode character

Fixes #15512

See merge request !3885

Update diff blue & yellow to match design

<img src="/uploads/60e1351fb04ab1c8969685fbc8b61c88/Screen_Shot_2016-04-22_at_9.12.17_AM.png" width="500px">
<img src="/uploads/6812b22ec53f3041811261daa0584822/Screen_Shot_2016-04-22_at_9.12.05_AM.png" width="500px">

See merge request !3883

Replace '-n' with '--name' in docker related documentation

`-n` for `docker run` is outdated. We should use `--name` instead. This MR fixes the example in documentation.

Fixes #15174

See merge request !3908

Fix php-docker example (for new docker versions)

`/.dockerinit` file doesn't exists in new Docker versions. Instead `/.dockerenv` can be used. This MR fixes the PHP example which was working only for older Docker versions.

Fixes gitlab-org/gitlab-ci-multi-runner#1241

See merge request !3907

Triggers blur after clicking award button

![blur](/uploads/6cd53a5ac314e8048c656685935747e2/blur.gif)

Fixes #15511

See merge request !3881

Add new shortcuts

Closes #14904

- On a project: `i` To navigate to New Issue page.
- On a issuable: `l` To open Label dropdown on a issuable.
- Global: Typing `?` multiple times now toggles the modal.

See merge request !3686

Fixed issue with project dropdown links not being clickable



See merge request !3870

Don't break line in middle of word

<img src="/uploads/cceb1a4212ff7785ace03cd6468edf85/Screen_Shot_2016-04-21_at_3.32.00_PM.png" width="500px">

See merge request !3864

Fix error on commit builds page

This MR fixes error on commit builds page that occurs before CI commit
(Pipeline) had been updated.

Closes #15509

See merge request !3874

Add a branded 503 static error page

[ci skip]

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/15398

See merge request !3894

Upgrade jQuery Rails from 4.0.5 to 4.1.1

Upgrades jQuery to 1.12.1 and jquery-ujs to 1.2.1.

Changelogs:
- https://github.com/rails/jquery-rails/blob/master/CHANGELOG.md
- https://blog.jquery.com/2016/01/08/jquery-2-2-and-1-12-released/
- https://github.com/rails/jquery-ujs/releases

See merge request !3642

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

Closes #15509

Fix Error 500 due to stale cache when projects are renamed or transferred

See merge request !3865

Closes gitlab-org/gitlab-ee#506

Enable the EmptyRule SCSS Linter

Prevents empty SCSS rules from being included in the SCSS.

Also fixes the handful of lints caught by the linter.

Regarding the `.gh` rule in monokai.scss, which was added in [this commit](https://gitlab.com/gitlab-org/gitlab-ce/commit/bf079c24afb8ad2991a4eaf60a71a7bc45dd775d), it appears to be empty in [the original file as well](https://github.com/richleland/pygments-css/blob/master/monokai.css). So I think it's fine to delete the selector.

cc: @jschatz1 

See merge request !3769

Updated list of InfluxDB queries/config

See merge request !3840

This setup is quite a bit different from before. In the previous setup
raw data was kept around for 30 days and downsampled data for 7 days.
This became problematic for GitLab.com as the number of points and
series resulted in InfluxDB running out of memory when starting up
(besides taking up 30 GB of storage).

To work around this the new setup keeps raw data around for _only_ an
hour while keeping downsampled data around for 7 days. In turn all
Grafana dashboards _only_ query the downsampled data instead of also
querying raw data.

Based on rough calculations this setup needs around 2GB of storage for 1
week of data, excluding whatever is needed for storing the raw data
(this highly depends on the amount of traffic).

If users want to use this new setup they have to remove any existing
dashboards provided by GitLab.com and re-import the ones from the
Grafana dashboards repository
(https://gitlab.com/gitlab-org/grafana-dashboards/). Should users wish
to change their default retention policy the easiest way of doing so is
to simply drop the database and re-run the InfluxDB commands added by
this commit. Users who want to keep their default retention policy as-is
can simply create the "downsampled" policy and run the other commands.

[ci skip]

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

[ci skip]

Fix license detection to detect all license files, not only known licenses

Fixes #15470.

See merge request !3878

Prevent users from deleting Webhooks via API they do not own

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/15576

See merge request !1959

Fixes #15470.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Add posibility to define a hidden job without 'script' in .gitlab-ci.yml

References #15451

/cc @ayufan 

See merge request !3849

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/15576

Resolves #15101.

Hiding future dates on contribution calendar

Fixes #9036

See merge request !2628

Allow middle-click on a Todo row to open in a new tab



See merge request !3899