firewall: Filter only on RED and exclude any private address space

firewall: Filter only on RED and exclude any private address space

Since libloc is built as a tree we cannot simply exclude any address
space in the middle of it. Therefore we create some firewall rules
which simply avoid checking non-globally routable address space.

Fixes: #12499
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>