Add methods for manipulating neighborlists

[PicoCentauri]

Due to my latest work with neighbor lists, I think three additional methods could be useful

def remove_neighbor_list(self, options: NeighborListOptions):
   """remove a list from a `System` based on the provided `options`"""
   ...


def slice_neighborlist(
   self,
   options: NeighborListOptions,
   axis: str,
   labels: Labels,
):
   """Create a new sub list from an already present list."""
   ...


def split_neighborlist(
   self,
   options: NeighborListOptions,
   new_options: List[NeighborListOptions],
   axis: str,
   grouped_labels: List[Labels],
): 
   """Create multiple sublists based on a present list."""
   ...

The last two should work similar to the slice/split operation that we have on a TensorBlock.

Background: If you have hybrid model that works on top of classic force field that already defines fixed pairs for bonds/angle/dihedral interactions, it might be useful to exclude these fixed pairs in your model because interactions are already well parametrized with these fixed pairs.

[Luthaf]

I don't see how new_options for slice_neighborlist and split_neighborlist would be different from the options.

For handling excluded pairs, you would want to replace the existing NL with a new one containing only a subset, so the new_options would be the same.

[PicoCentauri]

For the slice_neighborlist I agree, but for the split you will get two or more lists and they can't have the same NeighborListOptions, right?