configs: Enable PIDs cgroup
My use case to is to allow Kubernetes master to run on Raspberry Pi 3.
Kubernetes introduced [Pid limiting](https://github.com/kubernetes/enhancements/blob/master/keps/sig-node/
20190129-pid-limiting.md),
on v.1.14.0 which includes [Pod Pids Limit](https://github.com/kubernetes/kubernetes/commit/
bce9d5f2043bd86964c9fec80d466e47776071bc)
and [Node Pids Limit](https://github.com/kubernetes/kubernetes/commit/
2597a1d97ef4d8f54b1ca661453e32794b756909#diff-fa76bb6ae2d9b4bb3d023737fe5e6029R333)
that requires pids cgroup.
See: https://github.com/raspberrypi/linux/pull/2968