Add a Upgrade button to group's billings page

Closes customers-gitlab-com#517

See merge request gitlab-org/gitlab-ee!14849

It adds an upgrade button to the group billings
page that redirects to the customers portal
upgrade checkout page.

If the user is not logged in at the portal he/she
will be automatically redirected after the login
process.

If the user is at the latest tier, the button
won't be presented.

Embed specific metrics chart in issue

Closes #62971

See merge request gitlab-org/gitlab-ce!31644

This MR adds the styles for displaying a single
chart next to another one when embedding them
in an issue.

Fix starrers counts after searching

See merge request gitlab-org/gitlab-ce!31823

Resolve "Broken master: Job Failed #274177103"

Closes #13587

See merge request gitlab-org/gitlab-ee!15302

Look up upstream commits once before queuing ProcessCommitWorkers

Closes #65464

See merge request gitlab-org/gitlab-ce!31871

Optimize DB indexes for ES indexing of notes

See merge request gitlab-org/gitlab-ce!31846

Expire project caches once per push instead of once per ref

Closes #52046

See merge request gitlab-org/gitlab-ce!31876

Previously `ProjectCacheWorker` would be scheduled once per ref, which
would generate unnecessary I/O and load on Sidekiq, especially if many
tags or branches were pushed at once. `ProjectCacheWorker` would expire
three items:

1. Repository size: This only needs to be updated once per push.
2. Commit count: This only needs to be updated if the default branch
   is updated.
3. Project method caches: This only needs to be updated if the default
   branch changes, but only if certain files change (e.g. README,
   CHANGELOG, etc.).

Because the third item requires looking at the actual changes in the
commit deltas, we schedule one `ProjectCacheWorker` to handle the first
two cases, and schedule a separate `ProjectCacheWorker` for the third
case if it is needed. As a result, this brings down the number of
`ProjectCacheWorker` jobs from N to 2.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/52046

Fix Arel deprecation warning in clusters_hierarchy

See merge request gitlab-org/gitlab-ce!31916

To index notes, we exclude system notes and use `find_in_batches` to
load them in batches for submission to the ES bulk import API.
These queries often result in DB timeouts because the usage of
`ORDER BY id` results in the `notes_pkey` index being used.

This adds an optimized partial index, and removes the unused index
`index_notes_on_noteable_type` which is already covered for our
usage by the existing `index_notes_on_noteable_id_and_noteable_type`.

Newer versions of PostgreSQL (at least 11) are smarter about this and
use `index_notes_on_project_id_and_noteable_type` instead, so we might
be able to remove the partial index again in the future.

Instead of checking if a commit already exists in the upstream project
in its ProcessCommitWorker and bailing out if it does, we check the
existence of all commits in bulk in Git::BranchHooksService, so that we
can skip scheduling ProcessCommitWorker jobs for those commits
that already exist upstream entirely.

Skip ES commit results for deleted projects

See merge request gitlab-org/gitlab-ee!15236

Update selectors and page object to fix Secure test

Closes gitlab-org/quality/nightly#126

See merge request gitlab-org/gitlab-ee!15252

Remove Security Dashboard feature flag

See merge request gitlab-org/gitlab-ce!31820

This removes the group_overview_security_dashboard feature flag

Remove Security Dashboard feature flag

See merge request gitlab-org/gitlab-ee!15176

This removes the group_overview_security_dashboard feature flag

As mentioned in https://github.com/rails/rails/pull/29619, this removes
this warning message:

```
Delegating join_sources to arel is deprecated and will be removed in
Rails 6.0. (called from project_clusters_base_query at
app/models/clusters/clusters_hierarchy.rb:62)
```

Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/61451

Quarantining add_file_template_spec

See merge request gitlab-org/gitlab-ce!31908

Issue - https://gitlab.com/gitlab-org/quality/nightly/issues/127

Generate shareable link for specific metric charts

See merge request gitlab-org/gitlab-ce!31339

Adds a clipboard button to the metrics dashboard, that allows
copying a link to an individual chart.

Generate shareable link for specific metric charts - EE

See merge request gitlab-org/gitlab-ee!14938

Adds a clipboard button to the metrics dashboard, that allows
copying a link to an individual chart.

Merge branch '11750-epic-dates-from-milestones-don-t-work-when-using-epic-in-a-new-issue' into 'master'

Resolve "Epic dates from milestones don't work when using /epic in a new issue"

See merge request gitlab-org/gitlab-ee!15062

- Update an epic start and due dates (if these are not fixed)
when adding this epic to a new issue with milestone
- Cover the case that uses quick actions in the issue
description to add the epic

Regenerate gitlab.pot

Closes #13579

See merge request gitlab-org/gitlab-ee!15296