Separate selectable categories for Consoles / Systems and Arcade / Single Game cores

[detheavn]

As someone who would prefer to wait using all the arcade cores until Analogue implements a way to group these under 1 category, I'd love to see an category split. I created a little mockup below as an example :)

[Compeau]

The info to do this is already in the source json, each core has a property named "category" that can be "handheld", "console", "arcade", or "computer". Filter console and handheld into one list, arcade and computer into another.

[Compeau]

I made this change, but apparently I don't have permissions to push my branch to the repo.