Switch base image to distroless-iptables

[mattstam]

Roughly the same as @rikatz's rationale:

we need to reduce costs (and by reducing costs, reducing image size)
we need to use something with a smaller footprint and reduce the amount of packages, and as a result the amount of CVEs in image package.
kube-proxy exists in all nodes (unless you use a CNI that implements its features) so it is a good candidate

Same as kube-proxy and also keeping in sync with what they v1 did: kubernetes-sigs/ip-masq-agent@cf9563a

[Tatsinnit]

🚀☕️