Add capability for command and args

Both directives command and args should be added to overwrite the container's entrypoint and command.

Attention strange naming:

In docker it is called ENTRYPOINT and CMD (command), whereas their respective friends in the k8s world are called command (for the entrypoint) and args (for commands). It should look like this:

spec:
  containers:
    - name: test
      image: alpine:latest
      command: [ "/bin/sh" ]
      args:
        - "-c"
        - "echo"
        - "hello"
        - "world"

refs:

• https://kubernetes.io/docs/tasks/inject-data-application/define-command-argument-container/#running-a-command-in-a-shell
• https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.19/#container-v1-core