Fixes a migration that causes error on some legacy DBs

Closes #46862

See merge request gitlab-org/gitlab-ce!22761

Cannot add label to issue from board

Closes #51620

See merge request gitlab-org/gitlab-ce!22475

Top level clusters controller

See merge request gitlab-org/gitlab-ce!22438

Adds pagination to pipelines table in merge request & commit page

Closes #28249

See merge request gitlab-org/gitlab-ce!22696

Add scheduled flag to job entity

See merge request gitlab-org/gitlab-ce!22710

TokenAuthenticatable allows non-unique tokens

See merge request gitlab-org/gitlab-ce!22748

Remove ci_enable_scheduled_build feature flag

Closes #52183

See merge request gitlab-org/gitlab-ce!22742

Significantly cut memory and SQL queries when reloading diffs

See merge request gitlab-org/gitlab-ce!22725

Resolve "Links in tabs of the labels index pages ends with `.html`"

Closes #52548

See merge request gitlab-org/gitlab-ce!22716

Add index to find stuck merge requests.

Closes #45608

See merge request gitlab-org/gitlab-ce!22749

Remove gitlab-ui's progress bar from global

See merge request gitlab-org/gitlab-ce!22705

[master] Security kubeclient ssrf

See merge request gitlab/gitlabhq!2575

Change HELM_HOST in Auto-DevOps to work behind proxy

See merge request gitlab-org/gitlab-ce!22596

Looks like there are some legacy GitLab databases that have a NOT NULL
constraint for the `created_at` and `updated` fields.

This change fixes the migration by adding a default value to those
columns and I think we always should have it in mind when inserting DB
records through raw SQL.

Link Bitbucket Server from import index page

See merge request gitlab-org/gitlab-ce!22752

Fix "rails g migration" not always using migration templates

Closes #52651

See merge request gitlab-org/gitlab-ce!22592

Replace tooltip in markdown component with gl-tooltip

See merge request gitlab-org/gitlab-ce!21989

Reduce merge conflicts in the User model

See merge request gitlab-org/gitlab-ce!22697

Reserve more RAM for master process in Puma

See merge request gitlab-org/gitlab-ce!22741

To reduce the number of abstract methods, use polymorphic_paths for
collection routes. Unfortunately for member routes, polymorphic_paths
does not support namespaced classes, so still continue to override
methods.

We introduced hidden_clusterable_fields in this MR but it is no longer
needed as we have gone back to nested resource routes which should
provide the params such as `project_id`.

Also add missing interface in abstract class.

Use CI_COMMIT_REF_SLUG when building assets image

See merge request gitlab-org/gitlab-ce!22756

* Using CI_COMMIT_REF_NAME fails when the branch or tag contains special
characters

CE backport from  Added a search bar to `Admin > Geo > Projects`

See merge request gitlab-org/gitlab-ce!22747

Use merge_db_schema for db/schema.rb conflicts

See merge request gitlab-org/gitlab-ce!22692

This allows EE code to reuse the search partial and append additional
query parameters to it, and have it preserved when searching.

See https://gitlab.com/gitlab-org/gitlab-ce/issues/45608#note_113803790
for query and plan.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/45608.

Add dynamic timer for delayed jobs in job list

See merge request gitlab-org/gitlab-ce!22656

By preloading certain models with the diff, we can eliminate many N+1
queries. For a push to the staging GitLab.com www-gitlab-com repository,
this eliminates over 3000 SQL queries and appears to bring down the RSS
usage by several gigabytes.

Relates to https://gitlab.com/gitlab-org/gitlab-ce/issues/49703

This moves the `where` in the `has_many :keys` association in Project to
the Key model. This allows EE to override this method, instead of
modifying the source code directly.