Setup module: Additional facts when using ansible with Linux on System z

- Improved parsing of /proc/cpuinfo to take the specifics of Linux on
System z. ansible_processor and ansible_processor_cores are now
completed.
- Also improved virtualization facts in the same environment, parsing
the output of /usr/bin/lscpu to populate virtualization_type and
virtualization_role more precisely. If lscpu is not available, then
stick to the previous behavior.

This is a follow-up of pull-request 5324 (https://github.com/ansible/ansible/pull/5324)