Add attributes to enable security group matrix or non-anonymous access

[jaypipes]

Jenkins supports a variety of different authn/z mechanisms. In configuring Jenkins to support container-provided authentication, you need to modify the Jenkins root config.xml file and add in things like this:

 <useSecurity>true</useSecurity>
  <authorizationStrategy class="hudson.security.GlobalMatrixAuthorizationStrategy">
   ...

It would be great to be able to set node attributes that would allow non-anonymous setup for the installed Jenkins server.

[patcon]

See #23 :)