Add support to create containers using k8s API/kubectl

[fgalind1]

One pre-requisite on this option is a shared storage solution that can be shared as a persistent volume
between the runner pod and the container pod for externals, _work/_temp and _work/actions folders.

It adds a new container provider implementation KubernetesCommandManager besides DockerCommandManager

Container provider solution can be chosen via RUNNER_CONTAINER_PROVIDER environment variable.
If not provided it defaults to "docker". Options allowed: "docker" and "kubernetes"

Persistent volume used for the container pod is taken from RUNNER_PERSISTENT_VOLUME_CLAIM environment variable

Example:

kubectl get pods -n github-actions
NAME                                                              READY   STATUS    RESTARTS   AGE
...
github.runner-9cgfx-m49b2                            1/1     Running   0          7m1s
github.runner-9cgfx-m49b2-container                  1/1     Running   0          2m53s
github.runner-9cgfx-m49b2-service-1                  1/1     Running   0          2m50s
github.runner-9cgfx-m49b2-service-2                  1/1     Running   0          2m52s
...