general-functions.pl: Fix for bug #12865 - Static IP address pools - Add network...

general-functions.pl: Fix for bug #12865 - Static IP address pools - Add network - Name wit>

- The fix for bug #12428 removed spaces from the validhostname subroutine as hostnames are
   not supposed to have spaces
- This resulted in spaces no longer being allowed for the Static IP Address Pools names
- New subroutine created called validccdname. This allows letters, upper and lower case,
   numbers, spaces and dashes

Fixes: Bug #12865
Tested-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>