Deb/bext

Wheezy first for review, other OSes will be added / tested before merge.
In the RPM there's a sed expression here to reinsert the settings_directory directive into the newly migrated file, as the script itself doesn't know about this.  Do you need it here too?

https://github.com/theforeman/foreman-packaging/blob/rpm/develop/foreman-proxy/foreman-proxy.spec#L174-L175