Pass size of model data

[kpu]

We can't just pass a void * for the model data. There needs to be some validation that the size allocated by the client is consistent with the size encoded in the model.

[jerinphilip]

Does it make sense to abstract the datatype here (const void *data, size_t size) and reuse it for shortlist as well? I found the following in #28 (comment).

class MemoryGift {
  const char *data() const;
  size_t length() const;
  void early_free();
};

Does it make sense to bundle these for model, shortlist (seeing as to someone who'd use bytearray uses it for efficiency purposes) and unpack it at BatchTranslator (where these are loaded)? Vocabulary I'm not sure, but it's required at service as well.

[abhi-agg]

@XapaJIaMnu Can we close this issue? I think #94 was the last missing PR to close this one. Right?