Provide best practice information around adding badges to a GitHub repository

[versionbaygt]

Would be nice do document how to add Badges to README.md, namely coverege, which version of MATLAB supported, documentation, ...

[rpurser47]

My current thinking is to do a demo toolbox to demonstrate all the "how to do useful stuff with GitHub.com" things like GitHub actions, badges, working with File Exchange, etc. One of the challenges is how to store the data behind custom badges. Right now, I check them into the repository, which really isn't a very good solution.