*: add complete CNI support

This commit enables Kilo to work as an independent networking provider.
This is done by leveraging CNI. Kilo brings the necessary CNI plugins to
operate and takes care of all networking.

Add-on compatibility for Calico, Flannel, etc, will be re-introduced
shortly.

Dockerfile

@@ -1,6 +1,12 @@
+FROM alpine AS cni
+RUN apk add --no-cache curl && \
+    curl -Lo cni.tar.gz https://github.com/containernetworking/plugins/releases/download/v0.7.5/cni-plugins-amd64-v0.7.5.tgz && \
+    tar -xf cni.tar.gz
+
 FROM alpine
 MAINTAINER squat <lserven@gmail.com>
 RUN echo "@testing http://nl.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories && \
     apk add --no-cache ipset iptables wireguard-tools@testing
+COPY --from=cni bridge host-local loopback portmap /opt/cni/bin/
 COPY bin/kg /opt/bin/
 ENTRYPOINT ["/opt/bin/kg"]