Find best hyperparameters for all catalogs/entities

[tupini07]

We found the hyperparameters which performed best for discogs/musician in issue #361. This issue is to be a more in depth investigation, in which we find the best performing hyperparameters for all combinations of catalog/entities, for all classifiers.

• [ ] discogs/band
• [ ] discogs/musician
• [ ] musicbrainz/band
• [ ] musicbrainz/musician
• [ ] imdb/actor
• [ ] imdb/director
• [ ] imdb/musician
• [ ] imdb/producer
• [ ] imdb/writer

[tupini07]

As an idea: if hyperparameters are substantially different across catalog/entities, then we could load the different hyperparameters dynamically depending on which catalog/entity soweego is processing at a given time.