Unify interfaces/signatures of the nixtla-libraries

[sotte]

I'm really enjoying the nixtla-libs.
One thing that could be improved is consistency of the signatures. E.g. arguments are called h, sometimes horizon etc. See
https://github.com/Nixtla/mlforecast/blob/main/mlforecast/forecast.py#L391
https://github.com/Nixtla/statsforecast/blob/main/statsforecast/models.py#LL364C17-L364C17

It would be great if they were the same. This makes it even easier to move from statsforecast to mlforcast to neuralforecast.