Marqo Datastore Implementation

[OwenPendrighElliott]

Marqo Datastore

This PR adds an implementation for Marqo as the datastore. Marqo is a multimodal vector search engine with included inference for embeddings. This implementation will extract image URLs from queries to enable multimodal search. Marqo has its own inference included so users can also select from a wide variety of models for embeddings or even make their own indexes with custom models. You can see a toy example here.

[jn2clark]

Hi @isafulf - is there anything else @OwenPendrighElliott needs to do for the PR? Thanks!