detect.py: Adding cpu {cores|socket} counting

In addition of the number of logical cpu units we report via
cpu/numbers, let's report also the number of physical sockets & cores
per socket. That could will be useful for health_check.
detect: Using lshw to detect cpu specs

Previous approach of getting cpu specs via cmd line is almost wrong as
it breaks the self tests as results depends on the hw where the test is
run.

This patch changes the way to collect data by using lshw's output.

I'm also adding a specific test case to match configuration items from
lshw as the original didn't had any.