R1:bccc1e1244a1

Add a date range query to Macros

Summary:
Ref T1163. Ref T2625. This could probably use some tweaks, but I kept things mostly-generic.

I added a new control for freeform dates so we can have it render help or whatever later on.

Test Plan: See screenshots.

Reviewers: chad, btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2625, T1163

Differential Revision: https://secure.phabricator.com/D6084