Gitaly metrics check for read/writeability

Closes gitaly#1218

See merge request gitlab-org/gitlab-ce!20022

Resolve "`!` autocomplete does not work anymore"

Closes #48528

See merge request gitlab-org/gitlab-ce!20204

Enable frozen string for app/workers/**/*.rb

See merge request gitlab-org/gitlab-ce!20197

Merge branch '46546-do-not-pre-select-previous-user-s-when-creating-protected-branches' into 'master'

CE port gitlab-ee!6112

Closes #46546

See merge request gitlab-org/gitlab-ce!19714

CE-EE parity for spec/models

See merge request gitlab-org/gitlab-ce!20165

Client-side fix for Gitaly TreeEntry bug

See merge request gitlab-org/gitlab-ce!20176

Resolve "Copying ordered list to new comment becomes unordered"

Closes #40484

See merge request gitlab-org/gitlab-ce!18522

Partially addresses #47424.

Enable frozen string literals for app/workers/*.rb

See merge request gitlab-org/gitlab-ce!19944

Resolve "Search dropdown hides & shows when typing"

Closes #48461

See merge request gitlab-org/gitlab-ce!20187

Prior to this change, health checks checked for writeability of the NFS
shards. Given we're moving away from that, this patch extends the checks
for Gitaly to check for read and writeability.

Potentially some dashboards will break, as over time these metrics will
no longer appear as Prometheus doesn't get the data anymore.
Observability in the circuit breaker will be reduced, but its not
expected to be turned on and the circuit breaker is being removed soon
too.

Closes https://gitlab.com/gitlab-org/gitaly/issues/1218

Implement MR diff notes autosave feature

Closes #48300

See merge request gitlab-org/gitlab-ce!20114

Revert merge request widget button max height

Closes #48441

See merge request gitlab-org/gitlab-ce!20175

Update external link icon in header user dropdown

See merge request gitlab-org/gitlab-ce!20150

[ci skip]

Added Diff Viewer to new VUE based MR page

See merge request gitlab-org/gitlab-ce!20131

Resolve "QA: Deploy key cloning test sometimes can't find the QA element"

Closes #48243

See merge request gitlab-org/gitlab-ce!20181

Fixed eslint failure in IDE spec helpers

Closes #48490

See merge request gitlab-org/gitlab-ce!20182

Show file in tree on WebIDE open

Closes #45703

See merge request gitlab-org/gitlab-ce!19887

Resolve "Update environment scope for starter/core plans on cluster page"

Closes #47794

See merge request gitlab-org/gitlab-ce!20166

Bugfix for #48378 - Resetting value of input element to fix Chrome-specific issue

See merge request gitlab-org/gitlab-ce!20161

Move git calls for `Repository#update_branch` inside Gitlab::Git

See merge request gitlab-org/gitlab-ce!20168

Enable "prefer-destructuring" in JS files

See merge request gitlab-org/gitlab-ce!19943

Resolve "Remove unused bootstrap component CSS"

Closes #46831

See merge request gitlab-org/gitlab-ce!19257

Fix branch API can_push attribute and add specs

See merge request gitlab-org/gitlab-ce!20156

Resolve "Explain what Groups are in the New Group page"

Closes #47221

See merge request gitlab-org/gitlab-ce!19991