Preprocess Text: add Chinese segmentation module

Chinese texts need a special kind of tokenization. Their texts cannot be simply split by whitespace or characters. It would be nice to add a separate module for segmenting Chinese texts.

Option 1: [NLTK with Stanford segmenter](https://textminingonline.com/dive-into-nltk-part-vi-add-stanford-word-segmenter-interface-for-python-nltk).

Option 2: [Jieba](https://github.com/fxsjy/jieba#jieba-1).

I would try with NLTK first to avoid introducing new dependencies, then fallback to Jieba if NTLK proves insufficient.

Start by reviewing the existing text preprocessing modules in orange3-text, then compare the proposed NLTK Stanford segmenter and Jieba options linked in the issue. Decide which segmentation approach fits the add-on without unnecessary dependencies, and verify that the new module segments Chinese text as intended.

Written by the indexing model from the issue text.