LOS-1210: Improve resiliency of rhn certificate sync
This MR contains several fixes:
- A check is now performed to confirm that the systems we use for the purposes of syncing content from Red Hat do in fact have the "Academic Site License" subscription attached
- The list of systems to perform the above checks against are now defined via the variable
RHNCHECK_SYSTEMS
(comma separated) - It's no longer a requirement to hard-code the uuids of systems, these are now looked through the API based on the contents of
RHNCHECK_SYSTEMS
- Any part of the script that could encounter an error will now email administrators. Previously errors were only printed to stdout
- Various blocks of code have been moved to separate functions
- The code has been linted (via a separate commit)
Edited by Ben Morrice