add support for multiprocessing to spacy pipelines

[skunkwerk]

Is your feature request related to a problem? Please describe.
The BatchAnalyzerEngine which calls the Spacy engine's process_batch method doesn't seem to pass through any kwargs for setting the n_process or batch size.

Describe the solution you'd like
We should update process_batch to pass through kwargs to spacy's pipe method.

Describe alternatives you've considered
Haven't considered any.

Additional context
N/A

[omri374]

Hi, this is a great suggestion. In fact, we had a PR that was started some time ago but wasn't completed. If you're interested in contributing, that'd be great. #883