Allow users to be removed from systems

This will allow us to keep a list of users that are allowed explicitly not
allowed to access systems.

```
user_info:
 - name: someonewholeft
   state: absent
 - name: activeaccount
   type: admin
   github: true
```

The above settings would ensure that the user named "someonewholeft" is not
able to access the system and "activeaccount" is.