wireless-regdb: Use db.txt file for wlanap.cgi

wireless-regdb: Use db.txt file for wlanap.cgi

- db.txt is the text file version of the wireless settings by country database
- Using db.txt means that regdbdump from crda is not required by wlanap.cgi
- This patch copies the db.txt file from the source tarball to /lib/firmware/ where
   it can be read by wlanap.cgi
- This version of the patch renames the db.txt file to regulatorydb.txt
- Updated rootfile to include regulatorydb.txt

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Bernhard Bitsch <bbitsch@ipfire.org>
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>