Rewrite for Podman based infrastructure

Replace Docker buildx based container building with buildah configured
for running in a Forgejo runner that's inside a rootless Podman
deployment.

This also removes kubectl and ansible as my infrastructure is not going
to target these technologies for deployment.

builder.sh

@@ -0,0 +1,62 @@
+#!/usr/bin/env bash
+set -xe
+
+YQ_VERSION=v4.44.2
+NODE_VERSION=22.x
+PNPM_VERSION=v9.5.0
+
+ctr=$(buildah from "docker.io/library/debian:trixie-20250428")
+mnt=$(buildah mount $ctr) # Used to verify mounts work
+
+# Install dependencies
+buildah run $ctr -- apt-get update
+buildah run $ctr -- apt-get install -y --no-install-recommends \
+	buildah \
+	ca-certificates \
+	containers-storage \
+	crun \
+	curl \
+	git \
+	netavark \
+	openssh-client \
+	podman \
+	podman-docker \
+;
+
+# Configure container storage
+shared=/var/lib/shared/storage
+buildah run $ctr -- sh -c "sed /usr/share/containers/storage.conf \
+	-e '/^additionalimagestores/a"'\
+'"  \"$shared\"' \
+> /etc/containers/storage.conf"
+buildah run $ctr -- sh -c "\
+	mkdir -p $shared/overlay-images $shared/overlay-layers; \
+	touch $shared/overlay-images/images.lock; \
+	touch $shared/overlay-layers/layers.lock; \
+"
+
+# yq https://github.com/mikefarah/yq?tab=readme-ov-file#install
+buildah run $ctr -- sh -c "curl --silent --location \"https://github.com/mikefarah/yq/releases/download/$YQ_VERSION/yq_linux_amd64.tar.gz\" \
+	| tar --extract --gzip --to-stdout ./yq_linux_amd64 \
+	| install --owner=root --group=root --mode=0755 /dev/stdin /usr/local/bin/yq \
+;"
+
+# node https://github.com/nodesource/distributions?tab=readme-ov-file#using-debian-as-root-nodejs-22
+buildah run $ctr -- sh -c "curl --silent --location \"https://deb.nodesource.com/setup_$NODE_VERSION\" | bash"
+buildah run $ctr -- apt-get install -y --no-install-recommends nodejs
+
+# pnpm https://nodejs.org/api/corepack.html#upgrading-the-global-versions
+buildah run $ctr -- corepack install --global pnpm@$PNPM_VERSION
+buildah run $ctr -- corepack enable pnpm
+
+# Clear caches
+buildah run $ctr -- rm -rf /var/lib/apt/lists/*
+
+# Config
+buildah config \
+	--env BUILDAH_ISOLATION=chroot \
+	--env _BUILDAH_STARTED_IN_USERNS= \
+$ctr;
+
+buildah unmount $ctr
+buildah commit --rm $ctr $1