Deprecate “redirect object” creation

[amirbey]

User Story

A Federalist user should implement valid links throughout their site and not rely on the build process to create redirect objects for invalid links to valid links.

Background (Optional)

Acceptance Criteria

• site links generate 404 if invalid
• Change made live via deploy of garden build

After evaluating, edit this part:

Level of effort - Medium

Implementation outline (if higher than "low" effort):

• inform site operators of the upcoming change via email or site notification
• remove redirect object creation from the publish phase
• add a link checker? displayed in logging and report status to GitHub

[davemcorwin]

Captured in the Epic: #248