Check out Git[0]. Using a version control system is a critical skill in modern software development where you can check a "blame" report on a file's contents to see what last touched that place or to check a log for a history of the software. As for the quality of your notes and commit messages, that is alas something that requires a more personal development.

You can also put each project into its own Git repository and throw it up on a site like GitHub to host it.

[0]: https://git-scm.com/