Adds a policy-aware query class for selecting Releeph projects. This doesn't really change anything.
- Make ReleephProject implment PhabricatorPolicyInterface, beginning the long journey to make it policy-aware.
- Implement ReleephProjectQuery, for querying projects using cursor-based, policy-aware paging.
- Use it on the list view, so we load only ~100 projects instead of all of them.
- Tweaked some of the URI routing stuff to make it a little more consistent with common practices.
Reviewed By: edward
Maniphest Tasks: T2714
Differential Revision: https://secure.phabricator.com/D5390