* Remove unused account_params method in admin/accounts controller
* Introduce AccountFilter to find accounts
* Use AccountFilter in admin/accounts controller
* Use more restful routes admin silence and suspension area
* Add admin/silences and admin/suspensions controllers
* Add Admin::BaseController to wrap admin area
Extracts the setting of the `admin` layout and verifying that users are admins
to a common base class for the admin/ controllers.
* Add basic coverage for admin/reports and admin/settings controllers
Matt Jankowski