WIP: Add RegisteredRunner for CpuAffinity module

[yadij]

[yadij]

NP: this is not yet fully tested. Specifically the use of RegisteredRunner::finalizeConfig moves from enter_suid() to leave_suid() capabilities. I am not sure if that has any relevance to setting affinity on any other OS. The reconfigure actions do not appear to require enter_suid() so it may be unnecessary for the startup actions too.

[yadij]

Making a draft for now. I have essentially abandoned this approach, but am leaving the PR open in case someone wants to try and resolve the issues @rousskov identified with the current design.