Add a prometheus proxy API per environment

Closes #58375

See merge request gitlab-org/gitlab-ce!26841

CE Improve project avatar settings

See merge request gitlab-org/gitlab-ce!26589

Resolve "Queries which return multiple series are not working correctly"

Closes #59323 and #59324

See merge request gitlab-org/gitlab-ce!26514

Corrects an issue whereby queries which return multiple series results
were not rendering as multiple data series on the metrics dashboard

Extract target branch quick action to shared example

Closes #59570

See merge request gitlab-org/gitlab-ce!26933

Bump rack gem to 2.0.7

See merge request gitlab-org/gitlab-ce!27033

Fix MWPS doesn't work for merge request pipelines

See merge request gitlab-org/gitlab-ce!26906

Extend CTE search optimisation to projects

Closes #55170

See merge request gitlab-org/gitlab-ce!26908

Autocorrect with RSpec/ExampleWording cop

See merge request gitlab-org/gitlab-ce!26817

- rewords examples starting with 'should'
- rewords examples starting with 'it'

Note: I had to manually fixup "onlies" to "only"

Fix race condition in ApplicationSettingImplementation.create_from_defaults

Closes #59162

See merge request gitlab-org/gitlab-ce!26319

Add documentation for custom build directories

See merge request gitlab-org/gitlab-ce!20427

This adds documentation for:

- `CI_BUILDS_DIR`,
- `CI_CONCURRENT_ID`,
- `CI_CONCURRENT_PROJECT_ID`,
- `GIT_CLONE_PATH`,
- `GIT_CLEAN_FLAGS`

Adding perf testdata for MR diff tab

See merge request gitlab-org/gitlab-ce!26660

Add a service to proxy calls to Prometheus API

See merge request gitlab-org/gitlab-ce!26840

- Also refactor the get and json_api_get methods so that the get method
can be reused by the new proxy method.
- The new proxy method makes no changes to the request to the prometheus
server and response from the prometheus server. This allows it to be
used as a proxy to the Prometheus server, hence the name.

Quarantine failing tests

See merge request gitlab-org/gitlab-ce!27036

Remove EE-specific parts from FilteredSearchManager (CE-backport)

See merge request gitlab-org/gitlab-ce!27016

(cherry picked from commit a4d0b2435ff132da9bb238fea95672a6ddfd084d)

Fix IDE file dropdown

Closes #60021

See merge request gitlab-org/gitlab-ce!27015

Fix old image diff swipe view

Closes #56762

See merge request gitlab-org/gitlab-ce!26968

CE Backport: Re-use MR tabs styles to Epic tabs

See merge request gitlab-org/gitlab-ce!26935

IDE fix MR detection from fork

See merge request gitlab-org/gitlab-ce!26986

**Why?**
Currently the IDE loads a merge request based on only the
`source_branch` name. This means it loads MR's from
forks that have the same branch name (not good).

- This required updating the BE API to accept `source_project_id`

Show error when namespace/svc account missing

Closes #54506

See merge request gitlab-org/gitlab-ce!26362

Fixing single string values in the 'include:' keyword of gitlab-ci.yml validations

See merge request gitlab-org/gitlab-ce!26998

This fix is a followup to !24098 which introduced a validation of the
`include:` keyword of a gitlab-ci configuration file when triggered
from /ci/lint API calls.

However, there was a test case missing: the case of a single string as
value. I have added a test case for that which shows that the code was
not validating it correctly.

This commit fixes that to allow all `include:` valid inputs.

Fix capitalization of a sentence in CONTRIBUTING.md

See merge request gitlab-org/gitlab-ce!27021

Backport Resizable container component for gl-charts

See merge request gitlab-org/gitlab-ce!26843

* Fix up graph resize logic if navbar is collapsed

Add snapshot

This update has two important fixes:

1. It reverts the monkey patch introduced in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/23385 since
https://github.com/rack/rack/pull/1201 is now part of the release.

2. Preserve forwarded IP address for trusted proxy chains
(https://github.com/rack/rack/pull/1343).

Clarify the Runner registration and authentication tokens

See merge request gitlab-org/gitlab-ce!26996

MWPSService currently uses the old pipeline lookup method. It searches
related merge requests with pipeline.ref, however, this doesn't work
for attached/detached merge request pipelines.

Merge branch '9217-warn-on-git-fetch-over-ssh-if-the-secondary-is-lagging-the-primary' into 'master'

Display console messages, if available

See merge request gitlab-org/gitlab-ce!26692

Resolve "Hide Kubernetes cluster warning if project has cluster related"

See merge request gitlab-org/gitlab-ce!26749

Fix and expand Gitaly FindCommit caching

See merge request gitlab-org/gitlab-ce!27018