[fix] dead links in documentation

[kyle-cochran]

Describe the bug
From a list compiled by Dhruv Jain

1.	OTSK Mathematics:
1.	https://open-space-collective.github.io/open-space-toolkit-mathematics/html/index.html
1.	Documentation >> Python >> 404
2.	Tutorials >> C++ >> 404
3.	Tutorials >>Python >> 404
4.	Contribution >> Contributing guide >> blank

1.	README
1.	Documentation >> Python >> “files in the folder are more apt for tutorials”
2.	Tutorials >> C++ >> empty folder
3.	Tutorials >> Python >> notebooks >> “missing comments/description”