Adding KubernetesCommandLineCodeExecutor

[r4881t]

Fixes #49

• [x] KubernetesCommandLineCodeExecutor
• [x] optional component Setup
• [ ] Example Notebook
• [x] Documentation Update
• [ ] Test Cases

Checks

• [x] I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• [ ] I've added tests (if relevant) corresponding to the changes introduced in this PR.
• [ ] I've made sure all auto checks have passed.

[r4881t]

I believe this is not needed anymore as this executor is already added. https://microsoft.github.io/autogen/0.2/docs/topics/code-execution/kubernetes-pod-commandline-code-executor/