Iterate on Maniphest reports

Summary:

• These are still slow, awkward and hideous -- but slightly better than

before.

• Allow "open" reports to be sorted.
• Add a "burn" chart/table for assessing project volatility.
• Add navigation.

Test Plan: Looked at reports.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran, epriestley

Maniphest Tasks: T923

Differential Revision: https://secure.phabricator.com/D1737