firewall: don't need special trick for TCPMSS

It doesn't need to read MTU off the physical interface.
firewall: replace QoS by CeroWRT script

Unmodified (except functions.sh sourcing) from:
 https://github.com/dtaht/ceropackages-3.10/blob/master/net/sqm-scripts/files/usr/lib/sqm/simple.qos
 https://github.com/dtaht/ceropackages-3.10/blob/master/net/sqm-scripts/files/usr/lib/sqm/functions.sh
firewall: copy qos directory
firewall: also enable QoS for IPv6
Revert "firewall: also enable QoS for IPv6"

This reverts commit f6a1f1cd7298d3d8874c767ba08dc65c8df14e98.
firewall: revert all CeroWRT stuff

I get a panic otherwise...
flexget: only use RSS feeds with "verified" torrent

Nothing like that exists for The Pirate Bay, let's remove it. Adapt
others if possible.
firewall: fix IPv6 tunnel

During the move to a DHCP hook, the 6rd prefix was not correctly configured!
flexget: grab American Dad
Revert "flexget: grab American Dad"

This reverts commit bcf3584328874a4eb915f7d44ea9fecfbeeaff8a.
flexget: wait even more to get better audio
flexget: don't retrieve AAC audio

We don't know if this is stereo or 5.1. Prefer dd5.1 (whose priority is
below aac in Flexget) or no quality at all (which may be better than
stereo).