R1:cef7664d47e0

Move Project list to use ManiphestTaskQuery

Summary: We decided to move away from driving everything through the search
engine since it doesn't scale terribly well, so use ManiphestTaskQuery instead.
Also link the open count and tweak some display stuff.
Test Plan: Looked at project list, clicked open tasks link
Reviewed By: tuomaspelkonen
Reviewers: cadamo, aran, jungejason, tuomaspelkonen
CC: aran, tuomaspelkonen
Differential Revision: 608