Update EE > CE downgrade service removal steps

Closes #46441

See merge request gitlab-org/gitlab-ce!19034

Loosen the matcher in the MR creation test

Closes gitlab-qa#245

See merge request gitlab-org/gitlab-ce!19012

Fix api_json.log not always reporting the right HTTP status code

See merge request gitlab-org/gitlab-ce!19028

As described in https://github.com/aserafin/grape_logging/issues/45, if
a Grape error is caught by the handlers and a different return code
is returned, then the api_json.log would have a 500 error code
instead of the right value. Inserting the GrapeLogging middleware
after the Grape middleware fixes this problem.

Seen in https://gitlab.com/gitlab-com/infrastructure/issues/4249

Resolve "Web IDE: Previewing Markdown in Firefox doesn’t show a scroll bar"

Closes #45934

See merge request gitlab-org/gitlab-ce!18992

Add Keyboard shortcuts for "Kubernetes" and "Environments"

Closes #46427

See merge request gitlab-org/gitlab-ce!19002

Move API group deletion to Sidekiq

See merge request gitlab-org/gitlab-ce!18626

add specific details related to how the UX team uses labels to tackle issues

See merge request gitlab-org/gitlab-ce!18927

fix / assigne username wrapping problem has been fixed

See merge request gitlab-org/gitlab-ce!18986

NestingDepth (level 5) in pages/pipelines.scss

See merge request gitlab-org/gitlab-ce!18830

Fix group lists visual

See merge request gitlab-org/gitlab-ce!19010

Conditionally enable deprecation log messages

Closes #46158 and gitlab-com/infrastructure#4228

See merge request gitlab-org/gitlab-ce!18997

Resolve "Estimating a large amount results in a server error 500"

Closes #46193

See merge request gitlab-org/gitlab-ce!18964

Resolve "Dropdown actions in mini pipeline graph in mr widget don't work"

Closes #46381

See merge request gitlab-org/gitlab-ce!18976

Fix: Use case in-sensitive ordering by name for groups

See merge request gitlab-org/gitlab-ce!18553

[CE]  Resolve "Extract EE specific files/lines for some controllers"

See merge request gitlab-org/gitlab-ce!18994

* Reset p bottom margin for group lists to fix vertical alignment
* Remove double border for group lists to be consistent with project
lists
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Improve performance of Projects::PipelinesController#index

See merge request gitlab-org/gitlab-ce!18427

* master: (40 commits)
  Add changelog
  Update quick_start_guide.md
  Resolve "Opening Project with invite but without accepting leads to 404 error page"
  Respect the inheritance chain between Ci::Build and CommitStatus
  Remove unneccessary imports
  fixed copy to cliboard button in embedded snippets
  Fix Error 500 viewing admin page due to statement timeouts
  Grant privileges after database is created
  Only setup db in the first checkout!
  Project Sidebar: Split CI/CD into CI/CD and Operations
  Fix GPM content types for Doorkeeper
  Workhorse to send raw diff and patch for commits
  Refactor out duplication in runner_policy.rb
  Remove unnecessary runner.is_shared? checks in api because they are handled by policy
  Allow admin to assign shared runner to project through API
  Change policy list_runner_jobs -> read_runner
  Rename User#ci_authorized_runners -> ci_owned_runners
  Improve efficiency of authorized_runner policy query
  Use can? policies for lib/api/runners.rb
  Allow group runners to be viewed/edited in API
  ...

Resolve "NoMethodError: undefined method `present' for #<GenericCommitStatus:0x00007f6eacf34a40>"

Closes #46177

See merge request gitlab-org/gitlab-ce!18979

Merge branch 'docs/46042-document-that-project-templates-can-be-used-with-auto-devops' into 'master'

Resolve "Document that Project Templates can be used with Auto DevOps"

Closes #46042

See merge request gitlab-org/gitlab-ce!19009

Signed-off-by: Rémy Coutable <remy@rymai.me>

When displaying a project's pipelines
(Projects::PipelinesController#index) we now exclude the coverage data.
This data was not used by the frontend, yet getting it would require one
SQL query per pipeline. These queries in turn could be quite expensive
on GitLab.com.

When displaying the pipelines of a project we now preload the following
data:

1. Authors of the commits that belong to these pipelines
2. The number of warnings per pipeline, which is used by
   Ci::Pipeline#has_warnings?

== Commit Authors

Previously this data was queried for every Commit separately, leading to
20 SQL queries being executed in the worst case. With an average of 3 to
5 milliseconds per SQL query this could result in 100 milliseconds being
spent in _just_ getting Commit authors.

To preload this data Commit#author now uses BatchLoader (through
Commit#lazy_author), and a separate module
Gitlab::Ci::Pipeline::Preloader is used to ensure all authors are loaded
before they are used.

== Number of warnings

This changes Ci::Pipeline#has_warnings? so it supports preloading of the
number of warnings per pipeline. This removes the need for executing a
COUNT(*) query for every pipeline just to see if it has any warnings or
not.

When displaying the project pipelines dashboard we display a few tabs
for different pipeline states. For every such tab we count the number of
pipelines that belong to it. For large projects such as GitLab CE this
means having to count over 80 000 rows, which can easily take between 70
and 100 milliseconds per query.

To improve this we apply a technique we already use for search results:
we limit the number of rows to count. The current limit is 1000, which
means that if more than 1000 rows are present for a state we will show
"1000+" instead of the exact number. The SQL queries used for this
perform much better than a regular COUNT, even when a project has a lot
of pipelines.

Prior to these changes we would end up running a query like this:

    SELECT COUNT(*)
    FROM ci_pipelines
    WHERE project_id = 13083
    AND status IN ('success', 'failed', 'canceled')

This would produce a plan along the lines of the following:

    Aggregate  (cost=3147.55..3147.56 rows=1 width=8) (actual time=501.413..501.413 rows=1 loops=1)
      Buffers: shared hit=17116 read=861 dirtied=2
      ->  Index Only Scan using index_ci_pipelines_on_project_id_and_ref_and_status_and_id on ci_pipelines  (cost=0.56..2984.14 rows=65364 width=0) (actual time=0.095..490.263 rows=80388 loops=1)
            Index Cond: (project_id = 13083)
            Filter: ((status)::text = ANY ('{success,failed,canceled}'::text[]))
            Rows Removed by Filter: 2894
            Heap Fetches: 353
            Buffers: shared hit=17116 read=861 dirtied=2
    Planning time: 1.409 ms
    Execution time: 501.519 ms

Using the LIMIT count technique we instead run the following query:

    SELECT COUNT(*)
    FROM (
        SELECT 1
        FROM ci_pipelines
        WHERE project_id = 13083
        AND status IN ('success', 'failed', 'canceled')
        LIMIT 1001
    ) for_count

This query produces the following plan:

    Aggregate  (cost=58.77..58.78 rows=1 width=8) (actual time=1.726..1.727 rows=1 loops=1)
      Buffers: shared hit=169 read=15
      ->  Limit  (cost=0.56..46.25 rows=1001 width=4) (actual time=0.164..1.570 rows=1001 loops=1)
            Buffers: shared hit=169 read=15
            ->  Index Only Scan using index_ci_pipelines_on_project_id_and_ref_and_status_and_id on ci_pipelines  (cost=0.56..2984.14 rows=65364 width=4) (actual time=0.162..1.426 rows=1001 loops=1)
                  Index Cond: (project_id = 13083)
                  Filter: ((status)::text = ANY ('{success,failed,canceled}'::text[]))
                  Rows Removed by Filter: 9
                  Heap Fetches: 10
                  Buffers: shared hit=169 read=15
    Planning time: 1.832 ms
    Execution time: 1.821 ms

While this query still uses a Filter for the "status" field the number
of rows that it may end up filtering (at most 1001) is small enough that
an additional index does not appear to be necessary at this time.

See https://gitlab.com/gitlab-org/gitlab-ce/issues/43132#note_68659234
for more information.

Resolve "Opening Project with invite but without accepting leads to 404 error page"

Closes #42531

See merge request gitlab-org/gitlab-ce!17634