Migrate `LanguageModelFeaturizer` to GraphComponent interface

Overview of the Solution: Adapt the LanguageModelFeaturizer to the new GraphComponent interface. See the implementation proposal for further details.

• adapt create ~and load~ functions new signatures
• implement required_packages and supported_languages
• ~adapt persistence~
• rename train to process_training_data (this featurizer only adds features but doesn’t require training)
• support multiple messages in process (make sure to handle empty messages)

Definition of Done:

• LanguageModelFeaturizer adapted to the new GraphComponent interface
• Unit tests are adapted to adapted component
• Other tests (integration tests, etc.) don’t break (because they’d (for now) still use the old component implementation)

[wochinge]

The featurizer doesn’t need persisting, so you can omit the persist method. Only components which train themselves need a persist method

[wochinge]

No, that’s not needed