Merge branch '1811-very-poor-performance-creating-merge-request-regression-in-9-0-often-hits-60-seconds-timeout-on-small-requests' into 'master'

Resolve "Very poor performance creating merge request, regression in 9.0 - often hits 60 seconds timeout on small requests"

Closes #1811

See merge request !1522

Use `:empty_project` in worker, view, task, serializer, policy, migration, and mailer specs

See merge request !1524

CE -> EE port: cleanup application settings spec ee

See merge request !1498

Update database source documentation for 9.6 compatibility

Closes #1746

See merge request !1543

A new MR won't have an author necessarily, so use the current user in
that case.

Instead of performing `git log` for each file that's changed, do it for
all files at once. This stops git having to load large packfiles once
for each file in an MR.

This is always a suggestion, so the change in behaviour should be
fine. Increase the number of commits counted by squaring it, to allow
for the fewer calls to `git log`.

This is analogous to `git log -- foo bar baz`, but not the same as
`Gitlab::Git::Repository#log(path: 'foo bar baz')`, which would run `git
log -- 'foo bar baz'`.

adds timeout option to push mirrors

Closes #1907

See merge request !1439

CE -> EE port: System notes meta data

See merge request !1526

Ensure empty string & non-numeric values also result in an error.

The ApplicationSetting#restricted_visibility_levels= now takes care of
converting string formatted levels to integers.

EE already includes specs for the ApplicationSettingsController, so
ensure future changes will be easier to merge to EE.

Port of '23674-simplify-milestone-summary' to EE

See merge request !1511

Fix custom protected branch pattern jumping scroll position to top -- EE merge edition

Closes gitlab-ce#30149

See merge request !1523

[ci skip]

[ci skip]

Port of scrollable-secondary-tabs to EE

See merge request !1534

As per GitLab 9.0 LFS is supported in GEO

See merge request !1530

Include JavaScript test coverage in coverage badge

See merge request !1501

Port of "API: Make the /notes endpoint work with noteable iid instead of id" to EE

Closes #1875

See merge request !1518

Merge branch '1961-number-of-required-approvals-must-not-be-reset-when-changing-assignee' into 'master'

Resolve "Number of required approvals MUST NOT be reset when changing assignee"

Closes #1961

See merge request !1515

CE Upstream - Monday

Closes gitlab-ce#29897

See merge request !1517

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/30149

Use more semantic `<button>` element and prevent the form from
submitting.

Conflicts:
	app/assets/javascripts/protected_branches/protected_branch_dropdown.js
	app/assets/stylesheets/framework/dropdowns.scss
	app/assets/stylesheets/pages/projects.scss