Add CPU affinity to executed processes

[utam0k]

opencontainers/runtime-spec#1253

[keisku]

Hi, I am looking for an opportunity to contribute to youki and this issue looks interesting!
If my understanding is correct, we can use the runc code, startCommandWithCPUAffinity() that calls sched_setaffinity(2), as a reference.

Can I give this task a try?

[utam0k]

@keisku Thanks! I'll assign you. I'm looking forward to your PR ;)