DEPR: move NumericIndex._format_native_types to Index
This starts moving functionality from `NumericIndex`to `Index` in preparation to remove `NumericIndex` and include numpy int/uint/float64 in the base `Index`.

Also removes the `**kwargs`, as that wasn't used in the method.

I'm doing one method per PR, figuring that is easier to review. I could add ore per PR if you want.

xref #42717.
thanks @topper-123 