Add batched decorator

[ryantwolf]

Refactors batched to be in a decorator. This frees the user from having to be knowledgable about how the underlying DocumentFilter or DocumentModifier when initializing ScoreFilter or Modify respectively.

Unit tests pass. The following scripts were manually tested and work properly.

examples/classifier_filtering.py
examples/find_pii_and_deidentify.py
nemo_curator/scripts/find_pii_and_deidentify.py
tutorials/tinystories/main.py

The examples and other scripts have been manually tested to work.

[ayushdg]

Thanks for the changes! Just a couple of places with the stray batched argument but generally lgtm.
I like the idea of having batched be an attribute of the filters/modifiers. Prevents the caller from having knowledge of which variant should be used.