Add a "template" parameter to application default policies

Summary:
Ref T5681. Ref T6860. This doesn't do anything interesting on its own, just makes the next diff smaller.

In the next diff, policies become aware of the types of objects they're acting on. We need to specify which object type all the "Default View/Edit" settings are for so they get the right rules.

For example, a rule like "Allow task author" is OK for "View Policy" on a task, and also OK for "Default View Policy" on ManiphestApplication. But it's not OK for "Can Create Tasks" on ManiphestApplication.

So annotate all the "template"/"default" policies with their types. The next diff will use these to let you select appropriate rules for the given object type.

Test Plan:

• Used grep to find these.
• This change has no effect.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T5681, T6860

Differential Revision: https://secure.phabricator.com/D13251