refactor: Langchain v0.3 (#74)

* refactor: moved packages out of langchain community and fixed embeddings abstraction

* refactor: update requirements.txt

* ✓chore: removed long list of requirements.txt

* fix: mongo db query and  embed/upload

* refactor: change env var name

* docs: Atlas MongoDB update env var setting

* docs: MongoDB Atlas direction

* docs: update atlas mongoDB directions

* docs: add deprecated env variable

* refactor: mongo db env variable MONGO_VECTOR_COLLECTION backwards compatability add