R1:030726b144de

Improve implementation of ManiphestTaskQuery

Summary:
Currently, we have a single `projectPHIDs` field, and a separate flag which makes it act like AND or OR.

This is silly. Make two separate methods for setting `AND` vs `OR` projects. This also simplifies the implmentation.

This doesn't change the UI or any behavior (yet), it just makes the API more usable.

Test Plan: Loaded homepage, "All Projects" task view, verified queries made sense and returned correct results. Grepped for changed method name.