Remove "bin/repository edit" workflow

Summary:
Ref T10748. In D14250#158181, I accepted this conditional on removing it once Conduit could handle it.

Conduit can now handle it, or at least will be able to as soon as T10748 cuts over.

Test Plan: Grepped for repository edit.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10748

Differential Revision: https://secure.phabricator.com/D15839