Add cgroupsV1 flag to nodepools

[databus23]

This allows falling back to cgroups v1 for clusters > 1.18.

The node pool now has a cgroupsV1 boolean flag to bring up nodes with cgroups v1 enabled

Fallingback to cgroupv1 is possible without a reboot since flatcar 3033.2.4: https://www.flatcar.org/docs/latest/container-runtimes/switching-to-unified-cgroups/