document philosophy/roadmap

I think the philosophy of: "Don't trust the admins" really succinctly explains almost all features of the module.

In terms of purposes:

• Block super destructive features present in Drupal core/contrib (like the ability to execute PHP)
• Maybe outright prevent installation of some dangerous modules (anything that relies on bad judgement is a good tip off
• Track (log) actions which might be useful for a forensic review of what happened on a site

Anything else?