Revisit elemental release procedures

[davidcassany]

Few things to improve and elaborate around releases:

• Not all sources are in github (specs, dockerfiles, etc.)
  • I'd suggest adding a some sort of dist/obs/ folder within the repos to include those. In dist/obs there could be a README.md explaining the files in there are OBS specific and mostly used for SUSE's builds.
• Rebuild of RPMs on PRs
• Release candidate tags are useless, probably we should simply consider Stable as our RC once artifacts are in registry.suse.com
• Rearrange OBS projects to match IBS setup #711
• Arrange IBS project to built properly, SR is accepted, but images are not building
• A bot user should be used in OBS instead of my own user #712

[davidcassany]

I could not manage to test IBS as I wanted (mirroring registry.suse.com to registry.suse.de) but a clean deployment based on registry.suse.de artifacts went smooth.

I also struggled to set a custom certificate for registry.suse.de, looks like on every reboot the /etc/rancher/k3s/registries.yaml file is overwritten by something, looks like there is some k3s service or script creating this file on every reboot...

Closing this issue as a couple of missing parts are separated in devoted non urgent or blocked issues.