feat: Tutorial Module 1: LLM-Powered Application Framework (LangChain)

[anantmittal]

We obviously can't explain the entire LangChain package. So maybe we can talk about things that we plan to use in Module 2:

• Chaining
• Data Loaders
• Other abstractions LangChain provides for embeddings, etc.

We should probably avoid delving into words we haven't explained yet. For example, LangChain provides abstractions for multiple vector stores and embeddings, but we cover that in Module 2.

[anantmittal]

From discussion with @IshikaKhandelwal, @anujsinha3: Maybe focus on Why LangChain?, and Chaining, and keep other LangChain abstractions for Module 2.

[vanitech]

Addressed in https://github.com/uw-ssec/tutorials/blob/main/SciPy2024/module1/langchain.ipynb