phosphor-pid-control yaml->cpp now json

[Patrick Venture]

If you pick up the latest phosphor-pid-control patchset you may notice
it no longer uses build-time compilation.  There is a transition to
using run-time configurations, and phosphor-pid-control has taken
action from this.  Phosphor-pid-control can be configured with a json
file or via entity-manager with dbus.  It's my understanding that most
openbmc users are using entity-manager with phosphor-pid-control.
I'll be updating the downstream systems from yaml to json.  It's a
nearly identical configuration.  There is also an example available.

If you would like assistance moving your system from yaml native
recipe usage, let me know.  I'm more than willing to help you get
there!

Patrick