Update sample queries for the vector search lab

[bohyunjung]

This PR is a follow-up for #23, which includes:

• updates to the sample queries for the vector search lab, due to the decreased dataset size
• sample images now included in the repo instead of referring to external URLs
• get_embeddings can handle local images with paths not including http

All scenarios for basic vector search, pre-filtering, and hybrid are tested.

[ajosh0504]

Great work, thanks so much for this, @bohyunjung!