R1:7034ac3a5a4b

Route Maniphest detail view through common custom field code

Summary: Ref T418. Run all the meaningful stuff on the detail page out of shared code.

Test Plan: Looked at detail page, saw custom fields.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T418

Differential Revision: https://secure.phabricator.com/D7000