fff-hoods: Make possible to use fixed hoodfile

Add a complete hoodfile to /etc/hoodfile to use only this file

Signed-off-by: Christian Dresel <fff@chrisi01.de>
Reviewed-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
- Changed according to Adrian's review
Reviewed-by: Tim Niemeyer <tim@tn-x.org>