NLP - API support for word embeddings

[joaopauloschuler]

API could support existing word embeddings:
http://vectors.nlpl.eu/repository
https://nlp.stanford.edu/projects/glove/
https://fasttext.cc/docs/en/english-vectors.html
https://fasttext.cc/docs/en/crawl-vectors.html

[joaopauloschuler]

This is duplicate of:

• Create token embedding layer TNNetEmbedding #132 - Create token embedding layer TNNetEmbedding
• Create token end positional embedding layer TNNetTokenAndPositionEmbedding #133 - Create token end positional embedding layer TNNetTokenAndPositionEmbedding