Create merge request from email

Closes #32878

See merge request gitlab-org/gitlab-ce!13817

Small Gitlab::Git fixes for Gitaly

See merge request gitlab-org/gitlab-ce!15675

Second iteration of Move Kubernetes from service to Cluster page

Closes #35616 and #39826

See merge request gitlab-org/gitlab-ce!14805

Cache the forks in a namespace in the RequestStore

Closes #40625

See merge request gitlab-org/gitlab-ce!15663

Backport Extract epic nav into separate partial for easier CE => EE

See merge request gitlab-org/gitlab-ce!15655

[CE] Move git operations for squash and rebase into Gitlab::Git

See merge request gitlab-org/gitlab-ce!15673

Clarify the docs review process and mention the supported repos

See merge request gitlab-org/gitlab-ce!15573

Backport EE changes from refactor sidebar weight block Vue and move to Issue Boards

See merge request gitlab-org/gitlab-ce!15706

remove ambiguity about which resource type to be using for new sessions

Closes #39367

See merge request gitlab-org/gitlab-ce!15726

Prevent job link form rendering when user does not have permissions

Closes #40739

See merge request gitlab-org/gitlab-ce!15723

* new merge request can be created by sending an email to the specific
email address (similar to creating issues by email)
* for the first iteration, source branch must be specified in the mail
subject, other merge request parameters can not be set yet
* user should enable "Receive notifications about your own activity" in
user settings to receive a notification about created merge request

Part of #32878

See https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/3566

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

Closes gitaly#737

See merge request gitlab-org/gitlab-ce!15517

The former is in Ruby's core lib, so is more flexible.

Use custom User-Agent header in GCP Client requests

Closes #40583

See merge request gitlab-org/gitlab-ce!15705

Reduce pipeline chain life span to minimize side effects

See merge request gitlab-org/gitlab-ce!15716

Closes gitaly#737

Import axios utils in commons chunks

See merge request gitlab-org/gitlab-ce!15721

On the `show` of a project that is part of a fork network. We check if
the user already created a fork of this project in their personal
namespace.

We do this in several places, so caching the result of this query in
the request store prevents us from repeating it.

Show status of issuable links in wiki pages

See merge request gitlab-org/gitlab-ce!15694

issue note component rename

See merge request gitlab-org/gitlab-ce!15587