The benefit of digest pinning isn't that great for this project really
and it comes at the cost of more issues and additional renovate noise,
so just don't anymore.
Adjust renovate config accordingly as well.
Use a full image source and set and explicit version for all images in
Chaosknoten (docker-)compose files.
With Renovate now set up, it is feasible to explicitly set versions.
This groups the files and templates for each host together and therefore
makes it easier to see all the (config) files for a host.
Also clean up incorrect, unused docker_compose config for mumble and
clean up unused engelsystem configs.
