feat: Add Helm chart for kubernetes-mcp-server

This commit introduces a Helm chart for deploying the kubernetes-mcp-server to a Kubernetes cluster. The chart is located in the `charts/kubernetes-mcp-server` directory and includes templates for the deployment, service, service account, RBAC, and a configurable `values.yaml` file.

The chart allows for easy configuration of the server, including:
- Image repository and tag
- Service ports
- Resource limits and requests
- Application-specific settings via a `ConfigMap`
- RBAC permissions for the server to interact with the Kubernetes API

A README.md file is included with instructions on how to install and configure the chart.

Author: google-labs-jules[bot]