Currently we have an arcanist "staging" repository also hosted on arcanist. This duplicates all the repository objects in the phabricator search.

We would like to do one of several possible things:

1. Disable indexing of staging
2. Move staging to another place (this would require people to have two sets of credentials)
3. Figure out how to get phabricator to push staging somewhere else (rather than arcanist)
4. Trigger builds on diffs via harbormaster

Relates to T38