Resolve "Store MergeWorker JID on merge request, and clean up stuck merges"

Closes #31207

See merge request !13207

33874 confidential issue redesign

See merge request !12801

Resolve "User dropdown in filtered search does not load avatar on `master`"

Closes #35729

See merge request !13181

Migrate Repository#find_commits_by_message to Gitaly

Closes gitaly#443

See merge request !13268

Migrate Gitlab::Git::Repository#size to Gitaly

Closes gitaly#437

See merge request !13259

Issuables: Move some code from create services to Sidekiq workers

See merge request !13326

DeclarativePolicy: reduce iterations of the step set

See merge request !13352

Add two more metrics for CI/CD

See merge request !13039

Remove JS flicker on page load; UI tweaks

See merge request !13347

Group-level new issue & MR using previously selected project

Closes #34411

See merge request !13058

Store & use ConvDev percentages returned by Version app

Closes #35761

See merge request !13217

[EE Backport] Update log audit event in omniauth_callbacks_controller.rb

See merge request !13339

Backport changes in https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/2551 to CE

Closes #21391

See merge request !13275

Add Gitlab::Git::Blob.batch method

See merge request !13225

Improve mobile sidebar

Closes #35483

See merge request !13349

rather than iterating the whole remaining step set with
.all?(&:prevent?)

Resolve "Remove jQuery Nicescroll"

Closes #15664, #30860, and #35885

See merge request !13262

Upgrade to webpack v3.4.0

Closes #33902

See merge request !12298

Improve GitHub importer

Closes #27429

See merge request !12886

Allow projects to be started from a template

Closes #32420

See merge request !13108

Support group milestone references

Closes #34778

See merge request !13289

Set default options outside the raw_log method

See merge request !13346

Reset only migration models

Closes #36052

See merge request !13336

We had a lot of copied and pasted code, when the different elements were very
small and easy to get wrong.