Composer package cleanup

Builds on #1. Hopefully this can be merged if #1 gets merged? Or maybe this one can be merged instead? Not sure how GitHub workflow likes to handle this kinda thing. :)

I wanted to cleanup some things that were not needed and I wanted to prefer stable over dev. I also leveraged the newish autoload-dev stuff so depending on how old your Composer is you might need to update. I also removed the bin.