docs: Add example notebook showing how to use image contexts

[nabinchha]

I ported this notebook from GenerativeAIExamples into this repo.

[andreatgretel]

Should we add a pointer to the new tutorial in _README.md? (this becomes the Overview section in the docs)

[andreatgretel]

Also, it's probably a good idea to add an index entry inside mkdocs.yml

[nabinchha]

Should we add a pointer to the new tutorial in _README.md? (this becomes the Overview section in the docs)

Oh yea, thanks for the catch! Updated in 3178a45

[nabinchha]

Also, it's probably a good idea to add an index entry inside mkdocs.yml

Added in d8363c0.

[nabinchha]

@johnnygreco @andreatgretel new change:

• vlm tutorial notebook has been simplified to only to image summarization.
• update num_records to 2 for preview and 10 for create in all tutorial notebooks.
• updated .gitignore to ignore artifacts generated by make convert-execute-notebooks