Bring back AI models as const

[demosjarco]

In commit 7f3789c, modelMappings was removed and replaced by creating union types directly in the argument in the run() overloads. This removes the ability to get the models available at runtime.

Also putting the model names directly inline to each overload makes it difficult to retrieve the models for a task type outside of the run() method vs. externalizing each one individually (or as part of a namespace or other grouping method).

[CarmenPopoviciu]

@G4brym might have more insight into this?

[G4brym]

Hey @demosjarco maintaining a list of all models in code is difficult, as we are always adding new models and updating the inputs.
We decided to remove modelMappings and instead add api endpoints to will always have the most up to date informations.
We recommend users to get the list of models from this api endpoint, you can also retrieve the model input/output schema from this api endpoint.