Moves CreateFromBundle RPC to mandatory

Closes gitaly#944

See merge request gitlab-org/gitlab-ce!20144

Unify some admin controllers

See merge request gitlab-org/gitlab-ce!20147

Ancestor check is Gitaly only now

Closes gitaly#789 and gitaly#308

See merge request gitlab-org/gitlab-ce!20095

Write Config is mandatory

Closes gitaly#879

See merge request gitlab-org/gitlab-ce!20146

Prefer `expect_next_instance_of` over `expect_any_instance_of`

See merge request gitlab-org/gitlab-ce!20141

Remove Languages feature gate

See merge request gitlab-org/gitlab-ce!20128

Gitaly tree entry is mandatory

Closes gitaly#310

See merge request gitlab-org/gitlab-ce!20099

Notify conflict only for opened/locked merge requests

See merge request gitlab-org/gitlab-ce!20125

Make GFM Autocomplete configurable

See merge request gitlab-org/gitlab-ce!20066

Document how the new automatic review apps for docs work

See merge request gitlab-org/gitlab-ce!20149

Update project sidebar to work with EE feature Security Dashboard

See merge request gitlab-org/gitlab-ce!20101

Resolve "WebHookService doesn't handle user info with nil passwords"

Closes #46571

See merge request gitlab-org/gitlab-ce!19945

This was missed from
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/20130

Fixed the IDE commit list item loosing its active state

Closes #48125

See merge request gitlab-org/gitlab-ce!20138

This specific one isn't used on most machines, therefor low risk.

Closes https://gitlab.com/gitlab-org/gitaly/issues/944

This change makes closes another migration! And remotes tests around it,
mostly due to stubbing this was needed. Also, these are tested on the
Gitaly side too:
- https://gitlab.com/gitlab-org/gitaly/issues/791
-
https://gitlab.com/gitlab-org/gitaly/blob/6dd74543f6af8ebcf22aa10e39da004f388fdda5/internal/service/repository/fetch_remote_test.go

Closes https://gitlab.com/gitlab-org/gitaly/issues/789

Always run review app for docs-only branches

See merge request gitlab-org/gitlab-ce!20130

Enforce setting string as value of the CI/CD variable

Closes #48210

See merge request gitlab-org/gitlab-ce!20061

Closes https://gitlab.com/gitlab-org/gitaly/issues/879

[Rails5] Fix MysqlDateTimeWithTimeZone in rails 5

Closes #46275

See merge request gitlab-org/gitlab-ce!19613

Closes https://gitlab.com/gitlab-org/gitaly/issues/310

Unify spec/javascripts/test_bundle.js

See merge request gitlab-org/gitlab-ce!20136

Delete non-latest merge request diff files upon MRs merge

Closes #37639

See merge request gitlab-org/gitlab-ce!19670

Closes #48125

Merge branch '46396-recognise-when-a-user-is-trying-to-validate-a-private-ssh-key-part-1' into 'master'

(Part 1) Resolve "Recognise when a user is trying to validate a private SSH key"

See merge request gitlab-org/gitlab-ce!19994