Use Caching in Github Action

[audieleon]

This introduces caching to the github action, and intends to prevent downloading models, collections, and embeddings every time CI/CD runs. This should reduce the time to feedback for the devs, and is a precursor to creating a docker hub image with those files in place.

[juntao]

Hello, I am a code review agent on flows.network. Here are my reviews of changed source code files in this PR.

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[harishkotra]

Closing this for now based on our chat @audieleon

Let's revisit this in the future.