Mojo added to SpeedTests repo on github

I recently came across jabbalaci's SpeedTests https://github.com/jabbalaci/SpeedTests, and I made a PR to add Mojo, which got accepted today! The project's idea is to stick to the basic implementation pattern of the task without using language-specific tricks, so I just followed the Python implementation.

It's a insightful list of benchmark results, and Mojo is holding up pretty well.