Remove fallback to platform credentials for managed project-level clusters

Closes #62772

See merge request gitlab-org/gitlab-ce!29262

Project-level clusters that made use of this legacy
behaviour have been migrated to unmanaged clusters,
so we are now free to remove this fallback.

Migrate managed clusters that aren't using managed features to unmanaged

Closes #62772

See merge request gitlab-org/gitlab-ce!29251

Migrate clusters with no token to unmanaged

Closes #62772

See merge request gitlab-org/gitlab-ce!29648

Omit issues links in merge request entity API response

Closes #63546

See merge request gitlab-org/gitlab-ce!29917

using_docker_images.md: fix config.json path

See merge request gitlab-org/gitlab-ce!29791

The merge request widget has a section that includes which issues may be
closed or mentioned based on the merge request description. The problem
is that rendering and redacting Markdown can be expensive, especially
since the browser polls for the data every 10 seconds.

Since these links don't change much and are just nice to have, we only
load them on first page load. The frontend will use the existing data if
the data doesn't appear on subsequent requests.

This saves about 30% of the rendering time of this endpoint, which adds
up to significant savings considering that
`MergeRequestsController#show.json` is called over a million times a day
on GitLab.com.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/63546

Make deploy_boards doc clearer about its requirements

See merge request gitlab-org/gitlab-ce!29682

There are clusters that have Kubernetes namespaces
stored which are missing a service account token.
These namespaces are unable to be used for deployments,
so marking the clusters as unmanaged will allow the
platform credentials to be used instead.

Update Grafana and GitLab Monitor in component list

See merge request gitlab-org/gitlab-ce!29537

This commit checks off two of the three components in the table that we
added for the CEO Challenge in Contribute 2019:

* Grafana:
  https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/3272

* GitLab Monitor:
  https://gitlab.com/charts/gitlab/merge_requests/787

Update docs on how to run E2E tests

See merge request gitlab-org/gitlab-ce!29823

Add Gitaly data to the usage ping

See merge request gitlab-org/gitlab-ce!29893

Add documentation on epic add/remove child relations quick actions

See merge request gitlab-org/gitlab-ce!29860

Use next_instance_of instead of any_instance_of

See merge request gitlab-org/gitlab-ce!29905

Backport changes made by EE to various YAML configuration files

See merge request gitlab-org/gitlab-ce!29606

For prepended classes, we need to use `expect_next_instance_of`
instead of RSpecs `any_instance_of` variants.

Errors in application settings panel shows wrong panel

See merge request gitlab-org/gitlab-ce!25434

Fixed failing GraphQL file import

Closes #63527

See merge request gitlab-org/gitlab-ce!29900

Improve bug severity definitions and consolidate guidance for clarity

See merge request gitlab-org/gitlab-ce!29694

Add embedding support to metrics_dashboard

See merge request gitlab-org/gitlab-ce!29696

This commits adds support for metrics dashboards
for embedding. If the flag 'embedded' is provided
to the environments/id/metrics_dashboard endpoint,
the response will be suitable for embedding in
issues or other content.

This is a precursor for support for embedding
metrics in GFM.

Gitaly data wasn't available to the team, an this change is a first
iteration towards understanding what data we need and how to interpret
it. Later more values will be added.

For now the most important thing is the filesystem String Array, as that
includes data on ext4 exposure and NFS.

Part of: https://gitlab.com/gitlab-org/gitlab-ce/issues/60602

Render last commit widget with Vue

Closes #62766

See merge request gitlab-org/gitlab-ce!29419

To make this happen, we need to conditionally add the group_saml
strategy when running tests, but only on EE. This requires some changes
to Gitlab.ee? so that it can be used before/without loading the Rails
environment. We also have to change how we require a few files, so this
can run outside of Rails.

Gitlab::JsonCache#parse_value ensure string

Closes #63510

See merge request gitlab-org/gitlab-ce!29885

Master i18n

See merge request gitlab-org/gitlab-ce!29801

[skip ci]

Docs: Link issue statistics api endpoint in the docs

See merge request gitlab-org/gitlab-ce!29855

Update Docs for Container Registry API Delete Endpoints

See merge request gitlab-org/gitlab-ce!29709

Add version text and edit section

See merge request gitlab-org/gitlab-ce!29875

Edit new Zoom call link content

See merge request gitlab-org/gitlab-ce!29878