add openvpn to default kitchen

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
add tree to extra packages

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
add apparmor utils to default servers

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
add requirements for berkshelf on ubuntu

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>