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.

Readme.md

@@ -1,16 +1,14 @@
 # Builder
 
-Common docker image used for running application builds, CI pipelines, and deployment scripts based on Debian 12.
+Common container image used for running application builds, CI pipelines, and deployment scripts based on Debian Trixie.
 
 ## Tools included
 
-- `ansible` latest - https://www.ansible.com/
-- `docker` latest - https://www.docker.com/
-- `curl` bookworm - https://packages.debian.org/bookworm/curl
-- `git` bookworm - https://packages.debian.org/bookworm/git
-- `gpg` bookworm - https://packages.debian.org/bookworm/gpg
-- `kubectl` v1.30.2 - https://kubectl.docs.kubernetes.io/
-- `node` v20.x - https://nodejs.org/
+- `buildah` trixie - https://packages.debian.org/trixie/buildah
+- `curl` trixie - https://packages.debian.org/trixie/curl
+- `git` trixie - https://packages.debian.org/trixie/git
+- `node` v22.x - https://github.com/nodesource/distributions
 - `pnpm` v9.5.0 - https://pnpm.io/
-- `ssh` bookworm - https://packages.debian.org/bookworm/openssh-client
+- `podman` trixie - https://packages.debian.org/trixie/podman
+- `ssh` trixie - https://packages.debian.org/trixie/openssh-client
 - `yq` v4.44.2 - https://github.com/mikefarah/yq