Add new NLP encoder Google's Universal Sentence Encoder

[breznak]

See https://towardsdatascience.com/use-cases-of-googles-universal-sentence-encoder-in-production-dd5aaab4fc15

https://www.learnopencv.com/universal-sentence-encoder/

For #259 , #634

[breznak]

FYI @brev

[brev]

@breznak great find! I'll be pondering, and will be thinking about related topics (semantic folding, ordering, etc.). thanks.