Complete the egress classification for "pass-through" PPPoE packets

Implement the egress classification for IPv4 and IPv6 as a series of
tc u32 filters that specifically adress the relevant header bytes by
offset. This most probably wil only work with exactly the encapsulation
I tested with (PPPoE without VLAN), all offsets were confirmed with
loking at captured packets from the router:
tcpdump -s 200 -i ge00 -w ge00.cap
Here cerowrt was accessing the wan vie a PPPoE client using ge00 as
interface to the DSL-modem. This needs more testers.