docs(automations): Add new doc for Glossary Term Propagation Automation, other docs cleanup

[jjoyce0510]

Available in v0.3.7.

Cleaning up "Rollback" docs in a few places. We disabled this functionality until it's fully battle-tested, at which point we'll bring these docs back!

Checklist

• [ ] The PR conforms to DataHub's Contributing Guideline (particularly Commit Message Format)
• [ ] Links to related issues (if applicable)
• [ ] Tests for the changes have been added/updated (if applicable)
• [ ] Docs related to the changes have been added/updated (if applicable). If a new feature has been added a Usage Guide has been added for the same.
• [ ] For any breaking change/potential downtime/deprecation/big changes an entry has been made in Updating DataHub