add resources and learning paths for new technologies like Langchain, Vector Databases, OpenAI apis etc.

[kausmeows]

The past few months have been too hard to catch up on AI with so many new things being released one after the other. Some are mentioned below, research about such things and add some learning paths for the same-

Vector Databases and why they are important - Pinecone Qdrant
Langchain

Would be preferable to have these added under NLP section along with Huggingface issue mentioned here - #30