FFU/multi-rhel support relies on moving computes between different tripleo roles.

It will not work as-is in OSPdO as the role name is assumed to be static throughout the baremetal host management logic.

Changing roles without a scale-down and scale-up has always been explicitly not supported (and potentially dangerous) so adding support for moving nodes between roles should ideally not be exposed as a general feature - look for a workaround just for the multi-rhel use-case instead.