Langchain - Document loader basic functionality i.e `lazy load` implemented Issue #77

[aravindkarnam]

[simjak]

@aravindkarnam, could we have LangChain dependencies as optional extras? LangChain is quite a complex and heavy library, so it would be better to have a core crawl service and then add extra dependencies if needed, rather than binding them from the start.

[aravindkarnam]

@simjak, Agreed. The long term plan is to create a PR in langchain community repository for the crawl4ai langchain integration. We only started this here to get a first version out.

I'll add langchain dependancies as an extra here in the setup.py file. Sounds good @unclecode?

[unclecode]

@aravindkarnam Proceed, it totally make sense