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.
Merge pull request #969 from mulby/gabe/remove-users

Allow users to be removed from systems