modules/daf: support for first firewall rules

modules/daf: support for first firewall rules

the format of rules resembles libpcap filters,
but it also requires action that should be taken
when the filter(s) match.

the action can be anything the policy module
supports, and the filters can be both policy
module or view module based (so it's possible to
filter on source address and packet contents at
the same time)