Improve help and validation sections of maximum build timeout inputs

Closes #49434

See merge request gitlab-org/gitlab-ce!23586

Avoid 500's when serializing legacy diff notes

Closes #54793

See merge request gitlab-org/gitlab-ce!23544

[Backport] Extract system check rake task logic

See merge request gitlab-org/gitlab-ce!23395

Resolve "Use read_repository scope on read-only files endpoints"

Closes #54826

See merge request gitlab-org/gitlab-ce!23534

Remove merge:master job entirely

See merge request gitlab-org/gitlab-ce!23585

Apparently disabling it by checking for a variable doesn't actually
disable it.

[ci skip]

Fix list that doesn't render properly

See merge request gitlab-org/gitlab-ce!23574

Setup Jest test environment

See merge request gitlab-org/gitlab-ce!23406

fix: update the link to the new address.

See merge request gitlab-org/gitlab-ce!23524

Merge request pipelines

See merge request gitlab-org/gitlab-ce!23217

Don't request changelog for MR with 'meta' label

See merge request gitlab-org/gitlab-ce!23556

Extract code into IssueBoardEntity / serializer (follow up)

See merge request gitlab-org/gitlab-ce!23511

Add example email on push notification to docs

See merge request gitlab-org/gitlab-ce!23566

Namely the `ci-build` and `meta` labels.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Adjust divider margin to comply with design specs

See merge request gitlab-org/gitlab-ce!23548

Use a 32-byte version of db_key_base for web hooks

Closes #53659

See merge request gitlab-org/gitlab-ce!23573

This reverts commit b53ebd93

Update K8s project namespace and ServiceAccount if exist

See merge request gitlab-org/gitlab-ce!23525

This reverts commit ac5c20bd

Allow review app smoke test to fail for now

See merge request gitlab-org/gitlab-ce!23563

Make KUBECONFIG nil if KUBE_TOKEN is nil

See merge request gitlab-org/gitlab-ce!23414

Fixed diff files not expanding

Closes #54868

See merge request gitlab-org/gitlab-ce!23555

This reverts commit 22954f22

Geo: Backport of EE MR Geo: Fix push to secondary over SSH for LFS

See merge request gitlab-org/gitlab-ce!22856

For CE, #lfs_http_url_to_repo calls #http_url_to_repo where as for EE we
examine for a Geo setup so we can support push to secondary for LFS.

Added specs for #deploy_key_pushable?() and #type()

LfsToken::HMACToken#token_valid?() will be examined and if false, look
in redis via LfsToken::LegacyRedisDeviseToken#token_valid?().

Docs - Fix repository submodule API example

See merge request gitlab-org/gitlab-ce!23561

Upgrade GitLab Workhorse to v7.4.0

See merge request gitlab-org/gitlab-ce!23557