Create all Generic version of vectorizers

[TangoJP]

Underlying tokens for the vecotrizers don’t have to be of String type. Create a refactored version that takes any Vec<Vec>.

1. Detach vectorizers from tokenizer. Streamelined version (i.e. tokenizer -> vectorize) can be separately created later. So vectorizer should just take Vec of Vec
2. Maybe try using Box<_> somewhere.