Add some keys and policy fields to repositories

Summary:
  - Add some TODO'd keys.
  - Add policy fields.

Test Plan: Viewed repositories; created a new repository and verified it got the right default policy settings.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D7056
Render Maniphest fields in an application-transactions-compatible way

Summary: Improves transaction rendering for custom fields and standard custom fields.

Test Plan: See screenshot.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D7054
Allow repositories to be activate/deactivated in a transaction-aware way

Summary: Adds activate/deactivate action plus transactions.

Test Plan: See screenshot.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Differential Revision: https://secure.phabricator.com/D7057
Fix a bug where policy queries with cursor-based pagers and non-ID orders can go into infinite loops

Summary:
Ref T603. See inlines for an explanation. The case where I hit this was loading the "Pending Differential Revisions" panel in Diffusion when logged out, after making a repository public.

What happens is that we load 10 revisions (say, D1 .. D10) but the user can't see any of them. We then try to load the next 10, but since the pagination is ordered by date modified, we need to base the next query on the modified date of the last thing we loaded (D10). However, since we use the viewer's policies to load that cursor object, it fails to load, and then we just issue the same query over and over again, loading D1 .. D10 until we run out of execution time.

Test Plan: Interface now loads correctly.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T603

Differential Revision: https://secure.phabricator.com/D7059
Use RepositoryQuery along common pathways

Summary: Ref T603. Make common repository queries (in Conduit and DiffusionRequest) policy-aware. These tend to get caugh by something else anyway, but tighten them up.

Test Plan: The conduit change already provided `user` everywhere. I verified that and browsed some pages.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T603

Differential Revision: https://secure.phabricator.com/D7060