Add "User Projects" Filter to Maniphest

Summary:

• Adds "User Projects" filter to Maniphest.
• The filter expands the user(s) specified into a set of projects and issues a query on that project set.
• "View All Triage" button in Tactical Command's Needs Triage panel now points to User Projects-Need Triage filter.

Test Plan: - User Projects filter correctly displays only the tasks in projects the specified users are involved in.

Reviewers: epriestley

Reviewed By: epriestley

CC: keebuhm, ddfisher, allenjohnashton, epriestley, aran

Differential Revision: https://secure.phabricator.com/D1901