Setup for quadlet/systemd runtime management

Rather than setting up volumes and starting the pipglr container
manually, utilize quadlet + systemd.  Retain the old setup and execution
method, but move them into separate documentation.

Signed-off-by: Chris Evich <cevich@redhat.com>

quadlet/pipglr.container

@@ -0,0 +1,33 @@
+[Unit]
+Description=Podman-in-podman GitLab Runner
+Documentation=https://gitlab.com/qontainers/pipglr/-/blob/main/README.md
+After=pipglr-storage-volume.service pipglr-cache-volume.service
+Requires=podman.socket pipglr-storage-volume.service pipglr-cache-volume.service
+
+[Container]
+ContainerName=pipglr
+Image=registry.gitlab.com/qontainers/pipglr
+
+# Required to run containers inside a container and ensure
+# container can be managed with podman-restart.service
+# Note: See https://github.com/containers/podman/issues/20418
+PodmanArgs=--privileged --restart=always
+
+# A nested systemd is used to manage nested podman & gitlab runner services
+Systemd=true
+
+# Allow jobs access to utilize fuse-overlayfs, for example to build container images.
+Device=/dev/fuse
+
+# Must be owned by the gitlab-runner user
+Secret config.toml,uid=1001,gid=1001
+
+# Add network isolation from other containers
+Network=pipglr.network
+
+# Storage for nested container images and job cache
+Volume=pipglr-storage:/home/podman/.local/share/containers
+Volume=pipglr-cache:/cache
+
+# No need to preserve this between runs
+VolatileTmp=true