Updated MAC Starter release-log IA

Property	Value
description	Split MAC Starter repo releases from WordPress install variant streams and removed stale hub docs.
version	0.71.0
type	Update
related	MAC Docs, MAC Starter, MAC Starter Release History

• Added a mac-starter/repo release-history stream for mac-starter source-repo releases.
• Kept bricks and etch as MAC Starter stack streams for WordPress install variants.
• Added install URLs to MAC Starter Bricks and Etch variant landing pages.
• Removed stale Bricks Hub and Etch Hub docs and references.