Modernize ProjectQuery paging/ordering

Summary: Ref T7803. Move ProjectQuery off getReversePaging() / getPagingColumn() and onto order vectors.

Test Plan: Set project page size to 3 and paged back and forth.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7803

Differential Revision: https://secure.phabricator.com/D12357