gluon-mesh-vpn-fastd: use CAKE for bandwidth shaping

Use CAKE for shaping ingress as well as egress bandwidth shaping.

CAKE allows to better shape egress as well as ingress bandwidth. It not
only performs bandwidth shaping but also flow-queueing.

This in conjunction with the batadv flow dissector allows us to utilize
CAKE for all mesh-implementations currently supported in Gluon.

Signed-off-by: David Bauer <mail@david-bauer.net>