Change the "can see remote address?" policy to "is administrator?" everywhere

Summary:
Depends on D18970. Ref T13049. Currently, the policy for viewing remote addresses is:

• In activity logs: administrators.
• In push and pull logs: users who can edit the corresponding repository.

This sort of makes sense, but is also sort of weird. Particularly, I think it's kind of hard to understand and predict, and hard to guess that this is the behavior we implement. The actual implementation is complex, too.

Instead, just use the rule "administrators can see remote addresses" consistently across all applications. This should generally be more strict than the old rule, because administrators could usually have seen everyone's address in the activity logs anyway. It's also simpler and more expected, and I don't really know of any legit use cases for the "repository editor" rule.

Test Plan: Viewed pull/push/activity logs as non-admin. Saw remote addresses as an admin, and none as a non-admin.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13049

Differential Revision: https://secure.phabricator.com/D18971