Add config to prohibit impersonation

See merge request gitlab-org/gitlab-ce!23338

Make RemoteMirror's only_protected_branches default value consistent

See merge request gitlab-org/gitlab-ce!23410

Added frontend GraphQL docs

See merge request gitlab-org/gitlab-ce!23405

Adds gitlab.impersonation_enabled config option defaulting to true to
keep the current default behaviour.

Only the act of impersonation is modified, impersonation token
management is not affected.

Add a rebase API endpoint for merge requests

Closes #33705

See merge request gitlab-org/gitlab-ce!23296

Update documentation with note regarding restoring ssh host keys

See merge request gitlab-org/gitlab-ce!23392

Bump gitlab-shell to 8.4.3

See merge request gitlab-org/gitlab-ce!23429

Update Knative IP address docs

See merge request gitlab-org/gitlab-ce!23380

[11.5] Fix SSRF in project integrations

See merge request gitlab/gitlabhq!2611

[master] Resolve: "Provide email notification when a user changes their email address"

See merge request gitlab/gitlabhq!2587

[master] Resolve "Reflected XSS in OAuth Authorize window due to redirect_uri allowing arbitrary protocols"

See merge request gitlab/gitlabhq!2572

[master] Fix CRLF issue in UrlValidator

See merge request gitlab/gitlabhq!2627

[master] Resolve "Personal access token with only `read_user` scope can be used to authenticate any web request"

See merge request gitlab/gitlabhq!2583

[master]Fixed ability to comment on and edit/delete comments on locked or confidential issues

See merge request gitlab/gitlabhq!2612

[master] [pages] Possible symlink time of check to time of use race condition

Closes #2742

See merge request gitlab/gitlabhq!2638

[master] XSS in markdown following unrecognized HTML element

Closes #2732

See merge request gitlab/gitlabhq!2599

[master] Fix XSS in mermaid diagrams

See merge request gitlab/gitlabhq!2597

[master] Don't expose confidential information in commit message list

See merge request gitlab/gitlabhq!2626

[master] Resolve: Promoting a milestone is missing an authorization check

See merge request gitlab/gitlabhq!2598

[master] Do not follow redirects in prometheus service

See merge request gitlab/gitlabhq!2617

[master] Stored XSS for Environments

Closes #2727

See merge request gitlab/gitlabhq!2594

[master] Fixed read private group names

See merge request gitlab/gitlabhq!2589

[Master] Redact sensitive information on gitlab-workhorse log

See merge request gitlab/gitlabhq!2584

See https://gitlab.com/gitlab-org/gitlab-shell/blob/master/CHANGELOG

[master] Resolve: "Provide email notification when a user changes their email address"

See merge request gitlab/gitlabhq!2587

[master] Resolve "Reflected XSS in OAuth Authorize window due to redirect_uri allowing arbitrary protocols"

See merge request gitlab/gitlabhq!2572

Externalize strings from `/app/views/snippets`

See merge request gitlab-org/gitlab-ce!23351

Make add_reference cop accept a hash for :index

See merge request gitlab-org/gitlab-ce!23375

Bump GitLab Workhorse to 7.2.1

See merge request gitlab-org/gitlab-ce!23424

From https://gitlab.com/gitlab-org/gitlab-ce/issues/53515, we see the
backend appears to have inconsistent default values for this column:

* DB schema: false by default
* UI checkbox: false by default
* `RemoteMirror` model: true by default

This leads to unintended behavior where the boolean is activated if the
UI doesn't pass in a value for the checkbox.

Force better alignment in tables

See merge request gitlab-org/gitlab-ce!23393

Include new and edit links in breadcrumb for project milestones, group milestones, and labels

Closes #43998

See merge request gitlab-org/gitlab-ce!18515

Improve detail of resolve conflict docs

See merge request gitlab-org/gitlab-ce!22927

[master] Fix CRLF issue in UrlValidator

See merge request gitlab/gitlabhq!2627

[master] Resolve "Personal access token with only `read_user` scope can be used to authenticate any web request"

See merge request gitlab/gitlabhq!2583

[master]Fixed ability to comment on and edit/delete comments on locked or confidential issues

See merge request gitlab/gitlabhq!2612