Add diffusion.uri.edit for creating and editing repository URIs

Summary: Ref T10748. Brings the rest of the transactions to EditEngine, supports creating via API.

Test Plan:

• Created a URI via API.
• Created a URI via web.
• Tried to apply sneaky transactions, got rejected with good error messages. <_< >_>

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10748

Differential Revision: https://secure.phabricator.com/D15821