Translate param.Parameterized to pydantic.BaseModel

[ahuang11]

Jim mentioned adding what Marc and I shared on Discourse to param, perhaps as a util(?), or simply briefly mention in docs.
https://discourse.holoviz.org/t/how-would-i-create-a-parameterized-class-programmatically/3149/4?u=ahuang11

Note, this does not handle converting param methods at all; simply incompletely translating the parameters into fields.

The opposite issue (converting from pydantic -> param) can be found here: #809