Support for HoloViz Panel

[ahuang11]

Hi! Love the idea of using typing to create widgets (Panel sort of already does this, but not with native Python types).

I'd love to get Panel working with this!

Copying the example from homepage and replacing ipywidgets with Panel:

import typing # Python native 

import panel as pn  # popular UI library 

def input_widgets_basic(
    prompt: str = "Who is Oppenheimer?",
    advanced_features: bool = True,
    model: typing.Literal['GPT-3.5', 'GPT-4.0', 'Falcon-7B'] = 'GPT-4.0',
    max_token: range(100, 200, 20) = 140,
    openai_key: pn.widgets.PasswordInput = "1234556",
    )  -> str:
    pass

input_widgets_basic()

I get this

Instead of:

[ahuang11]

After talking to Forrest, I think param is probably more suitable since funix is mapping types to widgets, rather than using ipywidgets widgets.

However, maybe Panel can be used as a separate backend.