Full rewrite of majority of job token docs. Move
some content out to correct page, reorganize and clarify
most sections in the page to help reduce confusion
and bring page up to standards

This change set postpones the removal of the deprecated Terraform CI/CD
templates from milestone 17.0 to 18.0.

Those CI/CD templates will be removed as soon as CI/CD components
are available to self-managed customers.

part of:
https://gitlab.com/gitlab-org/gitlab/-/issues/439284

This is not supposed to be deployed until the release day.

GitLab's support for Ubuntu 18.04 is being deprecated in GitLab 16.8.
Startign with GitLab 17.0, packages will not be provided for Ubuntu
18.04.

Changelog: deprecated

- /data/deprecations/16-8-license-compliance-page.yml
- /data/deprecations/16-8-deprecate-license-list.yml

Rename file and rebuild deprecation doc

- /data/deprecations/16-5-remove-deprecated-metric-filter-from-dora-api.yml
- /data/deprecations/16-8-remove-deprecated-metric-filter-from-dora-api.yml

The Slack Notifications integration is deprecated. We have been
announcing that the integration will be removed in 17.0, however there
are a few blocking issues to its removal (mentioned in
https://gitlab.com/groups/gitlab-org/-/epics/8673) that have not been
done (as of time of writing, in 16.8).

We will extend the milestone we place to remove the Slack Notifications
integration from 17.0 to 18.0 in order to give us time to complete those
features.

https://gitlab.com/gitlab-org/gitlab/-/issues/435906

The errors were due to a missing closing quotation mark in the title.
Also ran the Rake task to regenerate the deprecations page.