create update channel
In contrast to the main project (#52034) the update projects are meant to start empty. So we create them manually
- The update projects (don't forget :NonFree) need to be created, including attributes (excl OBS:Maintained which will be added later).
- add the new projects to openSUSE:Maintenance meta
- The obs backend mapping file needs to be adjusted to to sync the repos to the correct place on download.opensuse.org