R1:5062abc53400

Most implement cursor paging in Maniphest

Summary:
Ref T2625. Depends on D6971. Maniphest is complicated to implement cursor paging for. Builds on D6971 to do so.

This is //almost// complete. Paging on projects and authors doesn't quite work, I'll clean that up shortly. Left some TODOs.

Test Plan: Set page size to `3`, paged forward and backward in a bunch of group/order modes. Results seemed to be as expected.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2625

Differential…