Slightly modernize Aphlict server status page

Summary:
Ref T4324. Add a real `Application` class. Use modern UI elements.

@chad, we could use an icon :3

Test Plan: {F114477}

Reviewers: chad, btrahan

Reviewed By: chad

CC: chad, aran

Maniphest Tasks: T4324

Differential Revision: https://secure.phabricator.com/D8254