Feature suggestions

This pull request contains the stuff I did in my vagrant-libvirt fork.
One of the 'bigger' features is the possibility to not use the management network to configure over ssh.
You can use a telnet connection on the serial port to automatically configure the initial network settings

This pull request  should be understood as some kind of suggestion. If I see people, that are interested
in these features I will make multiple 'more clean' pull requests for the different features.