Update Buildable search in Harbormaster

Summary:
Fixes T10011.

• Modernize searching for buildables.
• Prepare for harbormaster.buildable.search.
• Allow users to query by status (see T10011).
• Collapse the four weird "commit / diff / revision / repository" fields into two slightly less weird fields with more UI hinting?

Test Plan: {F1131918}

Reviewers: chad

Reviewed By: chad

Subscribers: Luke081515.2

Maniphest Tasks: T10011

Differential Revision: https://secure.phabricator.com/D15356