RFC: docker: Add SELinux labels for rootless Podman compatibility

Volumes need to be properly labelled so it can run as rootless Podman containers.

The SELinux re-labeling bind mount option is ignored on platforms without SELinux, so it shouldn't break existing setups.

@brocaar Any comments about this? This makes things work out of the box on Fedora and shouldn't cause any issues to other distros/OS's as these labels are ignored when SELinux is not enabled.

https://docs.docker.com/storage/bind-mounts/#configure-the-selinux-label