Add new option to generate subtitles by a specific number of words (#1729)
* ADD parser for new argument --max_words_count
* ADD max_words_count in words_options
ADD warning for max_line_width compatibility
* ADD logic for max_words_count
* rename to max_words_per_line
* make them kwargs
* allow specifying file path by --model
* black formatting
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Co-authored-by: Jong Wook Kim <jongwook@nyu.edu>