feat: Disable progress bar logging at inference time.

[radandreicristian]

• Add a progress bar flag in the CorefModel constructor.
• Add a default value in the Spacy configuration.
• Add the constructor argument with default value set to True in subclasses.
• Move the core of _inference to a separate method to avoid duplicate code.
• Display the progress bar in _inference only if the progress bar flag is set.

See https://github.com/shon-otmazgin/fastcoref/issues/16

[radandreicristian]

It should be good to go now, I've also tested it, and there are no errors.

Might have rushed the PR a bit last time.

Thanks for the comments @shon-otmazgin