[Feature request] Ability to change default from FAS to FAL

[AndreasHerss]

I am building an app, with pro icons, using the FAL icons for everything, and importing using the library method.

It would be really nice if i could specify the default to be FAL instead of FAS in my App.js, just like i define the library and icons for that. This would clear and remove redundant code everywhere i use icons.

Right now i feel more like just importing them in every component, as opposed to using library, as the code is clearer.

It would of course be nice to be able override it, for that one use case where i would need a FAS or FAR icon.

I don't see this as a breaking change, as the current syntax could be kept, and the default in "FontAwesomeIcon.js" would just need a "fallback" to FAS if none is specified by me in my App.js.