Since the switch to Git backed sources for SL-Micro 6.0, staging
workflow does not work anymore for SUSE:ALP:Products:Marble:6.0. This
patch drops all related pipelines. Additional it adds the same checkers
for the SUSE:SLFO:Main project.
For some reason, valid yaml is not supported - the indentation required
is rather wild. But to check the syntax before commit, you can use the
plugin locally: