This uses a monotonic time instead of the timeofday provided by the
Kernel.

The timeofday is subject to change, if an administrator changes it
manually, or is updated by NTP.

This makes the request duration histograms consistent across both
metrics and only records it when the request was successful.

It also makes sure that the way the error was received in the
middleware does not matter anymore. Before this change, an error that
bubbled up towards the middleware would count towards a groups error
budget, but not towards the service availability. With this, both metrics
will not include durations of requests that resulted in responses with
a 5xx status code.

If a request failed, it's not very important for users how fast it
failed.

For our metrics it could also skew results: A very fast 500 would have
less impact on a service's availability or a groups budget spend than
a slow one. While they should weigh the same. Similarly, a slow
failure should not count double towards availability.

This results in the following scoring for requests:

|         | Fast | Slow |
|---------|------|------|
| Success | 2/2  | 1/2  |
| Error   | 0/1  | 0/1  |

Quarantine spec/initializers/mailer_retries_spec.rb due to flakiness

See merge request gitlab-org/gitlab!63326

Add documentation for opt-in graphs

See merge request gitlab-org/gitlab!63031

Add invite source to call to the invite members modal

See merge request gitlab-org/gitlab!62723

Improve cross-linking between MR approvals + API

See merge request gitlab-org/gitlab!63677

Adds tooltip for pipeline editor branch switcher

See merge request gitlab-org/gitlab!63675

Merge branch '333063-follow-up-from-enforce-json-schema-validation-for-generic-security-report-fe' into 'master'

Pipeline Security Dashboard: move props to inject

See merge request gitlab-org/gitlab!63719

Use issuesCount field when fetching board issues count [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!63404

Add ability to store CI trace chunks on Gitlab::Redis::TraceChunks [RUN ALL RSPEC] [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!62938

Updated nav guidance for 14.0 changes

See merge request gitlab-org/gitlab!63688

Boards - Remove unused milestone related code [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!63714

Add switch branch tooltip to
the branch switcher on the pipeline
editor.

Update translations levels for June 2021

See merge request gitlab-org/gitlab!63469

Display Escalation Policy

See merge request gitlab-org/gitlab!63416

Update Migration and Secrets steps in Reference Architecture docs

See merge request gitlab-org/gitlab!63504

Fix Releases page pagination after sort change

See merge request gitlab-org/gitlab!63434

Add Free tiers to Pages docs

See merge request gitlab-org/gitlab!63559

Add test for updating default branch in projects API

See merge request gitlab-org/gitlab!63711

Add Free tier badges to Pages-related product docs

Remove graphql deprecated fields

See merge request gitlab-org/gitlab!63293

Add order_project_path to package graphql API sort

See merge request gitlab-org/gitlab!62473

Add unique index on configuration for batched_background_migrations

See merge request gitlab-org/gitlab!63599

Global Search - SearchableDropdownItem Component

See merge request gitlab-org/gitlab!63567

Create new way of encrypting tokens - phase 2- writer [RUN ALL RSPEC] [RUN AS-IF-FOSS]

See merge request gitlab-org/gitlab!58902

Changelog: changed

Reorganized runner content to bring SaaS shared runners to main page

See merge request gitlab-org/gitlab!63572

Add code snippet generation for DAST Configuration

See merge request gitlab-org/gitlab!63530

Remove ENABLE_LOAD_BALANCING_FOR_FOSS as it is now ready for production use

See merge request gitlab-org/gitlab!63627

Fix wording on DevopsAdoption

See merge request gitlab-org/gitlab!63288

Add auto-generation of iterations for iteration cadences

See merge request gitlab-org/gitlab!62348

Add epic's note system_note_meta to Import/Export

See merge request gitlab-org/gitlab!63551