Add bin/repository edit for CLI repository editing

Summary:
Ref T4039. This is mostly to deal with that, to prevent the security issues associated with mutable local paths. The next diff will lock them in the web UI.

I also added a confirmation prompt to bin/repository delete, which was a little scary without one.

See one comment inline about the --as flag. I don't love this, but when I started adding all the stuff we'd need to let this transaction show up as "Administrator" it quickly got pretty big.

Test Plan: Ran bin/repository edit ..., saw an edit with a transaction show up on the web UI.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T4039

Differential Revision: https://secure.phabricator.com/D7579