Move to JuliaAstro

[icweaver]

Hi Stefan, it was nice messaging with you earlier. I've just sent you an invite to JuliaAstro. I think this will allow you to transfer your repo when you are ready, and then we can update links to point to the right place. Here's an example of how that might look. Happy to help provide more info if anything comes up

Remaining to-dos

• Transfer repo
• Update codecov token
• Update links Canonize #7