Resolves #13

Because we are using openwrt and we would like to mantain LUCI running
on it's interface we can't bind on 0.0.0.0. or 127.0.0.1 hence we must
listen on a specific ip. This will set the public ip from the group
vars to be the one where we listen

This role split the reverse proxy configuration in three files per
host. Every file belong to a different directory that is created on
the reverse proxy we use (nginx).

The server, map and upstream directives can be splitted into
different files to be included into the nginx.conf configuration.