Create Documents Site

Work on making a document section to create an attractive documents page

https://github.com/mdp0023/SVInsight/tree/main/doc 

Example documentation sites:

- https://mdp0023.github.io/SVInsight/
- https://heli-xu.github.io/findSVI/ (looks like some of the documents are in the https://github.com/heli-xu/findSVI/tree/main/vignettes)