Summary:
- In ProjectQuery, always load the viewer's membership in the project because we need it to perform a CAN_VIEW test.
- Add storage for the view, edit and join policies.
- A user can always view a project if they are a member.
- A user can always join a project if they can edit it.
- Editing a project requires both "view" and "edit" permissions, and edit does not imply view.
- This has no effect on the application yet.
Test Plan: See next diff.
Reviewers: vrana, btrahan
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T603
Differential Revision: https://secure.phabricator.com/D3219
