No package uses l2tp_ip.

xt_CT was added to kmod-ipt-conntrack a while back. Update our
GLUON_SPECIALIZE_KERNEL rules accordingly.

When building xt_CT into the kernel, one of the symbols IP_NF_RAW and
IP6_NF_RAW must be enabled as well, even though there is no runtime
dependency when building as modules. The kernel grows by less than 1KB
even when both IP_NF_RAW and NETFILTER_XT_TARGET_CT are enabled, making
this change a (very slight) net win in both flash and RAM usage.

This is a fix for the broken ingress traffic-shaping in gluon v2018.2.2
and possibly earlier.

For ingress traffic shaping the kernel option NET_ACT_POLICE is needed.
Before this patch there was no dependency to this. Neither in
gluon_core, gluon-mesh-vpn-core nor in the package.

This patch adds this dependency.

[Matthias Schiffer: move dependency from GLUON_CORE to gluon-mesh-vpn-core]

Fixes #1790

The redirect and dnat target are needed for gluon-alt-esc-client to
forward frames to the selected, alternative gateways.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>