Add a specific Dockerfile for simple k3s

Dockerfile

+FROM golang:1.15.2-alpine3.12
+
+# Prepare the build environment
+RUN apk -U --no-cache add bash git gcc musl-dev docker vim less file curl wget ca-certificates jq linux-headers zlib-dev tar zip squashfs-tools npm coreutils \
+    python2 openssl-dev libffi-dev libseccomp libseccomp-dev make libuv-static sqlite-dev sqlite-static libselinux libselinux-dev zlib-dev zlib-static
+RUN mkdir -p /go/src/golang.org/x \
+ && cd /go/src/golang.org/x && git clone https://github.com/golang/tools && cd tools \
+ && git checkout -b current aa82965741a9fecd12b026fbb3d3c6ed3231b8f8 \
+ && go install golang.org/x/tools/cmd/goimports \
+ && rm -rf /go/src /go/pkg
+
+# Actually build k3s
+ENV GO111MODULE off
+ENV STATIC_BUILD true
+
+COPY . /go/src/github.com/rancher/k3s
+WORKDIR /go/src/github.com/rancher/k3s
+
+
+RUN mkdir -p etc build/static build/data
+RUN scripts/validate
+RUN scripts/build
+RUN scripts/package-cli
+
+# Prepare the result image
+FROM alpine:latest
+RUN apk -U --no-cache add libseccomp iptables ip6tables socat ethtool pigz coreutils findutils bash
+COPY --from=0 /go/src/github.com/rancher/k3s/dist/artifacts/k3s /go/src/github.com/racher/k3s/package/entrypoint.sh /usr/local/bin/
+ENTRYPOINT ["/usr/local/bin/entrypoint.sh"]
+

package/entrypoint.sh

+#!/bin/sh
+
+mount --make-shared /
+exec /usr/local/bin/k3s "$@"