R1:bd0be1c650ea

Add View, Edit and Join policies to PhabricatorProject

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…