fix(privileges) Add Term Groups as targetable entities for privileges

[chriscollins3456]

In response to this issue.

Adds Glossary Nodes (aka Term Groups) to be targetable entities for adding / editing metadata privileges.

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

[github-actions]

Unit Test Results (build & test)

517 tests  ±0   517 ✔️ ±0   8m 36s ⏱️ -35s
121 suites ±0       0 💤 ±0 
121 files   ±0       0 ❌ ±0 

Results for commit ba99d4a. ± Comparison against base commit 5bf5fc2.