Add a way to list all available models I can use with %%ai

[JasonWeill]

Problem

There is no command I can run to get a list of models I can use with the %%ai magic command.

Proposed Solution

Add a command such as %%ai list that lists all supported models.

[dlqqq]

Each provider exposes a class attribute called models, for example:

>>> AI21Provider.models
[
    "j1-large",
    "j1-grande",
    "j1-jumbo",
    "j1-grande-instruct",
    "j2-large",
    "j2-grande",
    "j2-jumbo",
    "j2-grande-instruct",
    "j2-jumbo-instruct",
]

Some providers are "registry" providers that have a dynamic, unknown, or extremely large list of supported models. For example, HuggingFace Hub is a good example. In this case, the returned list is just the wildcard specifier ["*"].

The %%ai list command should do a good job of rendering a long list of models in a human-readable format (i.e. not a raw list that extends all the way to the right). Furthermore, there should be some helpful messaging when a model provider is a registry provider. Perhaps each registry provider could have a help message stored as a class attribute that tells users how to discover new models.

• HuggingFace Hub: "Available models can be found on https://huggingface.co/"
• SageMaker Endpoint: "Available endpoint names can be found on your AWS Console."