List all properties docs on admin page

[mosabua]

Description

• see commit messages
• provides better visibility for the fact that there are a lot of pages with more details without messing up the left hand nav on properties
• improve linkage to concepts page and content about data sources, catalogs, and connectors

Additional context and related issues

na

Release notes

(x) This is not user-visible or is docs only, and no release notes are required.