Add K8s/OpenShift synthetic mock data for testing

[suriya-93]

• Added data_set_k8s.py with comprehensive synthetic K8s cluster data
• Added k8s_example.py following readme_example.py pattern
• Supports all 5 UI component types (one-card, table, set-of-cards, video, image)
• All data is synthetic (example.com domains, generic names) for testing purposes
• Enables ~225 test prompts (2x more than movie dataset)
• Ready for API integration.
• All helper functions follow existing patterns from data_set_movies.py.

[velias]

Thanks for providing this PR. I'm only thinking what to do with it ;-) Movie data available in next_gen_ui_testing are used in unit tests in other modules. I'm not sure if we need more data of this type here.
Also libs/next_gen_ui_langgraph/readme_example.py is here so we know the code runs before it is placed into README.md of that module. I'm not sure if we need more examples here, nobody will run this example probably. BTW there is also another repo dedicated to examples https://github.com/RedHat-UX/next-gen-ui-examples ;-)
I'm thinking where to use your data to provide the most value. It might be more useful if this data would be part of the data providing agent (now called movie agent, but we can rename it and let it to provide more data types in response) in the E2E testing app. Testing app should be our easy to start/use offering.
@lkrzyzanek @Hrithik-Gavankar