Add KNK Notes

**Is your feature request related to a problem? Please describe.**
No notes for this course.

**Describe the solution you'd like**
Notes added somewhere made in a nice & readable way.

**Describe people you want to have a look**
@MaharnavS

**Additional context**
Add Notes PDFs in ./Notes folder & add their buttons in notes.html file

Start with notes.html and the ./Notes folder mentioned in the issue. Add the KNK Notes PDFs and corresponding buttons, then verify that the notes page presents the new entries clearly and that each button links to the intended PDF.

Written by the indexing model from the issue text.