Split common_install recipe in two recipes

We now have common_config (which generates the config files) and
common_agent (which is used for everything related to linuxbridge/ovs
agent).
Do not create sudoers file on SUSE

It's already packaged.
Simplify server recipe by moving things out

All bits for a l3 role are moved to the new l3 recipe.

The code immediately restarting services after config changes moved to
post_install_conf since this is where it's needed.
Group ovs code paths together