Update d3 to v4 to enable tree shaking (and reduce the size of our webpack bundles)

Closes #37013

See merge request gitlab-org/gitlab-ce!15585

Revert "Move Repository#write_ref to Git::Repository#write_ref"

Closes #41143

[ci skip]

See merge request gitlab-org/gitlab-ce!16055

Migrate to Project#empty_repo?

Closes #41326

See merge request gitlab-org/gitlab-ce!16054

This reverts merge request !15712

Changed layout_nav to ES module

See merge request gitlab-org/gitlab-ce!16003

Resolve "Search merge-requests with API"

Closes #38318

See merge request gitlab-org/gitlab-ce!16029

Specify how we're utilizing rspec for bin/qa

See merge request gitlab-org/gitlab-ce!16040

Merge branch '39246-fork-and-import-jobs-should-only-be-marked-as-failed-when-the-number-of-retries-was-exhausted' into 'master'

Fork and Import jobs only get marked as failed when the number of Sidekiq retries were exhausted

Closes #39246

See merge request gitlab-org/gitlab-ce!15844

Add BlocksJsonSerialization model concern and include it in User

Closes #37947

See merge request gitlab-org/gitlab-ce!14350

* master: (21 commits)
  Prevent some specs from mangling the gitlab-shell checkout
  Line up search dropdown with other nav dropdowns
  Fix onion-skin re-entering state
  Remove related links in MR widget when empty state
  Show inline edit button for issues
  Fix tags in the Activity tab not being clickable
  Fix shortcut links on help page
  Don't link LFS-objects multiple times.
  [CE->EE] Fix spec/lib/gitlab/git/gitlab_projects_spec.rb
  Tidy up the documentation of Gitlab HA/Gitlab Application
  Make sure two except won't overwrite each other
  Update axios.md
  Remove transitionend event from GL dropdown
  Preserve gem path so that we use the same gems
  Load commit in batches for pipelines#index
  BlobViewer::PackageJson - if private link to homepage
  Do not generate links for private NPM modules in blob view
  Remove block styling from search dropdown
  Fix sidebar height when performance bar enabled
  Remove all dropdown animations and set display: none if they're not open
  ...

Remove animations from dropdowns

Closes #41186

See merge request gitlab-org/gitlab-ce!15968

Don't link LFS-objects multiple times.

Closes #41241

See merge request gitlab-org/gitlab-ce!16006

- Ensure that unwanted params are no passed to actual finder classes

Previously, this would include the entire User record in the update
hash, which was rendered in the response using `to_json`, erroneously
exposing every attribute of that record, including their (now removed)
private token.

Now we only include the user ID, and perform the lookup on-demand.

Fix spec failures in spec/lib/gitlab/git/gitlab_projects_spec.rb

Closes #41264

See merge request gitlab-org/gitlab-ce!16015

Fix onion-skin re-entering state

Closes #38533

See merge request gitlab-org/gitlab-ce!15815

Remove related links in MR widget when empty state

Closes #36764

See merge request gitlab-org/gitlab-ce!15888

Show inline edit button for issues

Closes #37474

See merge request gitlab-org/gitlab-ce!15812

Fix tags in the Activity tab not being clickable

Closes #33028

See merge request gitlab-org/gitlab-ce!15996

Do not generate links for private NPM modules in blob view

Closes #36020

See merge request gitlab-org/gitlab-ce!16002

Improve performance of Pipelines#index.json

See merge request gitlab-org/gitlab-ce!14846

Fix shortcut links on help page

Closes #41097

See merge request gitlab-org/gitlab-ce!16001

If Unlinking a fork would fail somewhere after this, the LFS objects
might still be linked. Which would cause issues when trying to destroy
a project.