Create nl_nl.json

[ferriarnus]

Add Dutch lang files. Still not a 100% happy with it, as S.T.A.T.U.E is a hard one (and I need to spell-check it again).

[Mrbysco]

As of 3 days ago advancements have lang keys 😓

[ferriarnus]

Oh didn't see that, guess I'll have to add these then.

[Mrbysco]

I honestly don't mind, only do it if you want to else I'll just add the default English values so it won't show unlocalized keys :P This pr is already huge for us :)

Btw if you want the translator reward I'll need your mc username so I can add you to the reward list

[ferriarnus]

Now all keys should be in, but I'm gonna try and do another spellcheck pass. My mc name is Ferri_Arnus (chocking I know).

[Mrbysco]

Looks good so far :)