Streamline MD to HTML parsing

[sdthaker]

Currently, MD to HTML parsing is done manually and it only supports a couple of features. We want to implement full MD to HTML parsing support. This can be easily achieved using the library remark-rehype, just like how Docusaurus does it. Its usage is given here just for reference. The code changes must be tested thoroughly to make sure the parsing happens properly. Integrating this will bring parsing logic to just a few lines and will support all MD features out of the box.