Kubernetes Support: Dockerfile, Deployment YAML, and Usage Guide

[CosminL-DEV]

This PR introduces a comprehensive set of examples for running and testing Cadence workflows using containers in Kubernetes. It includes:

• A specialized Dockerfile (Dockerfile) to build images with Cadence samples.
• A Kubernetes YAML file (cadence-samples-pod.yaml) for easy test pod deployment.
• A detailed usage guide (README.md) with instructions for:
  • Registering the domain in Cadence.
  • Building and pushing the image to your registry.
  • Deploying the pod on Kubernetes.
  • Running and testing sample workflows (Hello World, File Processing, DSL).
  • Links to additional documentation and source code.

These additions make it easier to validate, learn, and automate workflow tests in Kubernetes environments.

[taylanisikdemir]

we can assume this dockerfile will be used within the repo context so no need to clone from github