Updates all the example provisioner scripts to use the new functions
exposed by the VMBuilder class as an illustration of how best to use
them.
Also adds a wrapper fail() handler to ensure the cleanup of the script,
as well as the global cleanup, are run on an exception.
Provisions Rocky Linux 8 and 9 systems, and potentially older
CentOS/Fedora/Scientific Linux/SuSE systems. Depends on a custom build
of rinse (3.7.1) with Rocky 9 support.
Joshua Boniface