Start work for using the go based signer

gosigner.Dockerfile

@@ -0,0 +1,20 @@
+FROM golang:alpine AS builder
+
+COPY cacert-gosigner /src/
+
+RUN set -ex ; \
+    cd /src/signer ; \
+    go build .
+
+FROM alpine/socat:latest
+
+COPY --from=builder /src/signer/signer /app/
+
+COPY docker/run-gosigner usr/local/bin/
+COPY docker/signer-config/* /srv/caconfig/
+COPY testca /srv/testca/
+
+VOLUME /srv/ca
+
+ENTRYPOINT []
+CMD ["/usr/local/bin/run-gosigner"]