Fix issues for setting up catalogue upgrade hands-on

This issue is to keep track of the changes/fixes to streamline the hands-on for upgrading the catalogue a bit. There are some longer term fixes that we will be doing here, but for now this should at least get us the images required.

• Building an image with older CTA RPMs doesn't work yet
• See if we can get the catalogue-updater chart to work without mounting the yum repos stuff.