Make the Drydock repository operation page slightly richer

Summary:
Ref T13164. See PHI788. The issue requests a "created" timestamp.

Also add filtering for repository, state, and author.

Test Plan:
Used all filters.

Reviewers: amckinley

Reviewed By: amckinley

Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam

Maniphest Tasks: T13164

Differential Revision: https://secure.phabricator.com/D19574