Safari Support

[braxtonhall]

This is a hard maybe, only because of the stupid OAuth

Safari does NOT support the identity API, so we'd need to do OAuth the way we did it the first time.

For something like this, I'd like to use OOP, and a browser singleton. If Safari, return the Safari browser implementation with hand rolled/error prone OAuth. Else? Do what we normally do.

References:

• https://stackoverflow.com/questions/65476966/oauth-redirect-url-in-the-new-safari-web-extension
• https://stackoverflow.com/questions/27477650/how-to-use-oauth-with-github-in-a-safari-extension