Create rebrandable documentation site with Kubernetes configuration (#782)

The ValidMind documentation site Docker image now supports full customization for white-label deployments and branded environments.

Configurable branding & URLs

• Customize product names in both long and short forms.
• Replace the ValidMind logo and favicon with your own SVG assets.
• Set custom URLs for your ValidMind platform and JupyterHub instances.

Local development support

• Kind (Kubernetes in Docker) integration is now available for local development.
• Use simple make commands to set up a local Kubernetes environment.
• Access real-time log viewing and cluster management.

For detailed setup instructions and configuration options, refer to Create a rebranded docs site. For a sample configuration, see validmind-docs.yaml.