make document loaders a standalone crate in repo

[cs50victor]

Is your feature request related to a problem? Please describe. A clear and concise description of what the problem is. Ex. I'm always frustrated when I want to use document loaders for a simple task but I have to import the entire langchain crate

Describe the solution you'd like A clear and concise description of what you want to happen. I would love to import document_loaders from the langchain repo directly in my toml file.

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context Add any other context or screenshots about the feature request here.