ModelIO -- move vocab and embedding related API to EmbeddingIO

[nicolay-r]

#282 proceeds.
Reason: It allows us reduce dependency from model_io. Model io keeps innformation about the saved state only, not embeddings and vocabularies as it was before.

• move get_model_embedding_filepath and get_model_vocab_filepath
• remove exp_ctx dependency from EmbeddingIO. (model_io)
• remove ExperimentContext since it includes only model_io.
• remove BaseModelIO then

Here, it shows that we just pass its contents to EmbeddingIO. Nothing special from ModelIO side:

AREkit/arekit/contrib/networks/core/model_io.py

Lines 59 to 63 in 5803b45

	def get_model_embedding_filepath(self):
	return self.__embedding_filepath
	def get_model_vocab_filepath(self):
	return self.__vocab_filepath