Add a "Project" field which can be empty or have more than one project, but only a maximum of one "heavyweight" project, where "heavyweight" projects are defined by project types that we add in T390.
- Pro: Addresses both the policy and tagging use cases. Not so ugly.
- Con: Probably way harder for users to figure out than (3).
Original ask: When I create a Mock in Pholio, I want to assign it to a Project for sorting / discovery. Bonus points for adding a filter search as well.