Allow OAuth applications to be disabled instead of destroyed

Summary: Ref T7303. This interaction is very oldschool; modernize it to enable/disable instead of "nuke from orbit".

Test Plan:

• Enabled applications.
• Disabled applications.
• Viewed applications in list view.
• Generated new tokens.
• Tried to use a token from a disabled application (got rebuffed).
• Tried to use a token from an enabled application (worked fine).

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T7303

Differential Revision: https://secure.phabricator.com/D15620