Move ManiphestTaskQuery to EdgeLogic

Summary:
Ref T4100. Share all edge logic code across applications.

• Internalizes the "check that the viewer can see projects" check into edge logic.
• Adds some convenience functions. Some of these aren't really all that convenient, but it's rare that we actually apply project constraints to queries in the applications -- and most of these callsites will go away in the long term -- so I didn't go too crazy with providing a simpler withProjectPHIDs() universal API or anything.

Test Plan:

• Grepped for all affected symbols.
• Tried to violate policies.
• Used workboards.
• Used normal Maniphest queries.
• Used maniphest.query.
• Verified the special grouping behavior works as expected.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T4100

Differential Revision: https://secure.phabricator.com/D12526