Cutom key definitions / add rhyper

[Vermoot]

Hi!

I know this has been asked before, especially before some other keywords/key definitions were added, but it was never added to skhd:

It'd be real nice to be able to create our own aliases for keys/key combinations.

My particular use case right now would be to add a rhyper key, meaning a hyper key using the right set of modifiers, so that I could use binds such as rhyper + cmd - j.

[honeybyhomo]

I have created this as a pull request: #336