Add an online Documentation tool to CQP4RDF

[thesagarsehgal]

Currently, the complete documentation is written in the Readme.md and other in docs folder. It would br nice to have an online version of th documentation.

After searching I found MkDocs would be good tool to wite the documentation as we can directly write in Markdown only.
Link to MkDocs:- https://www.mkdocs.org
How to get started with MkDocs:- https://docs.readthedocs.io/en/stable/intro/getting-started-with-mkdocs.html

Further, we can host the documentation online on readthedocs. It offers free hosting of documentation.
Hosting MkDocs documented website on Read The Docs:- https://www.mkdocs.org/user-guide/deploying-your-docs/#read-the-docs