Initial support for gensim 4

[raffaem]

Experimental initial support for gensim 4.

Fixes #9 and #7

[pbadillatorrealba]

Hello @raffaem

Thank you very much for your contribution.
I am currently finishing up some pretty big changes about how the query embeddings are obtained.
The main change is that now all operations with embeddings will be in the WordEmbeddingModel class.
Due to the above, I will not be able to merge your branch directly. However, I will be able to easily integrate your contribution without major problems.

I hope this week to be releasing the new version of the software.

Thank you very much!
Pablo.

[raffaem]

So I guess this is no longer needed