I created an unofficial documentation for Synthmaster 3

[Carcar]

I noticed there were no written documentation and only the videos on YouTube, so I went ahead and created an unofficial docs that I hosted on my GitHub: https://github.com/CSumm/unofficial-synthmaster3-manual.

Hopefully this can be a starting point for the official docs, or if not, at least help people learn how to use the tool. There also might be things missing or incorrect since I did rely on automation for this, so feel free to add issues to it, or make PRs for it.