This is a bit of an RFC commit, I noticed that when we discussed
a crash from the worker we looked at individual message from
syslog/journald for the stacktrace deatils. I was wondering if
having a more direct crash report would be more useful? We can
of course also add more logrus features to flag those with tags
like "crash" or something (I did not do that in this PR, I don't
know much about the operational side, sorry).
Move the OSBuildStagesToRPMs function, associated test, and RPM type
from the worker into the rpmmd subpackge. We will use this function in
the cloud API to compile the NEVRAs for the new metadata endpoint.
