Make Maniphest list page react to viewer capabilities

Summary:
Ref T603. Basically:

• Hide "Reports".
• Hide "batch edit" and "export to excel".
• Hide reprioritization controls.
• I left the edit controls, they show a "login to continue" dialog when hit.
• Allow tokenizer results to fill for public users.
• Fix a bug where membership in projects was computed incorrectly in certain cases.
• Add a unit test covering the project membership bug.

Test Plan: Viewed /maniphest/ when logged out, and while logged in.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T603

Differential Revision: https://secure.phabricator.com/D7126