Add Docker image for Github Actions runner

This change adds configuration for a Docker image to be used as Github
Actions runner.

runner/Dockerfile

@@ -0,0 +1,53 @@
+FROM debian:bullseye
+
+ARG GITHUB_RUNNER_VERSION="2.301.1"
+
+ENV GITHUB_PAT ""
+ENV GITHUB_OWNER "fabianishere"
+ENV GITHUB_REPOSITORY "pve-edge-kernel"
+ENV RUNNER_WORKDIR "_work"
+
+RUN apt-get update \
+    && apt-get install -y \
+        curl \
+        sudo \
+        git \
+        jq \
+        devscripts \
+        debhelper \
+        equivs \
+        asciidoc \
+        bc \
+        bison \
+        cpio \
+        dwarves \
+        flex \
+        kmod \
+        libdw-dev \
+        libelf-dev \
+        libiberty-dev \
+        libnuma-dev \
+        libslang2-dev \
+        libssl-dev \
+        lz4 \
+        quilt \
+        rsync \
+        xmlto \
+        zlib1g-dev \
+        zstd \
+        python3-dev \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/* \
+    && useradd -m github \
+    && usermod -aG sudo github \
+    && echo "%sudo ALL=(ALL) NOPASSWD:ALL" >> /etc/sudoers
+
+USER github
+WORKDIR /home/github
+
+RUN curl -Ls https://github.com/actions/runner/releases/download/v${GITHUB_RUNNER_VERSION}/actions-runner-linux-x64-${GITHUB_RUNNER_VERSION}.tar.gz | tar xz
+
+COPY --chown=github:github entrypoint.sh ./entrypoint.sh
+RUN sudo chmod u+x ./entrypoint.sh
+
+ENTRYPOINT ["/home/github/entrypoint.sh"]

runner/entrypoint.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+registration_url="https://api.github.com/repos/${GITHUB_OWNER}/${GITHUB_REPOSITORY}/actions/runners/registration-token"
+echo "Requesting registration URL at '${registration_url}'"
+
+payload=$(curl -sX POST -H "Authorization: token ${GITHUB_PAT}" ${registration_url})
+export RUNNER_TOKEN=$(echo $payload | jq .token --raw-output)
+
+./config.sh \
+    --name $(hostname) \
+    --token ${RUNNER_TOKEN} \
+    --url https://github.com/${GITHUB_OWNER}/${GITHUB_REPOSITORY} \
+    --work ${RUNNER_WORKDIR} \
+    --unattended \
+    --replace \
+    --label bullseye
+
+remove() {
+    ./config.sh remove --token "${RUNNER_TOKEN}"
+}
+
+trap 'remove; exit 130' INT
+trap 'remove; exit 143' TERM
+
+./run.sh "$*" &
+
+wait $!