v3 Custom Node Schema

## Background
We are introducing a new way to define custom nodes to solve a few problems and add new functionality:
- Dynamic input / output types
- Easily use custom Vue widgets without writing JS
- Better type hints
- Outputs can be uniquely identified with a list
- Extensible for future functionality

[More info](https://blog.comfy.org/i/165338805/node-specification)

## In Scope

- Enable the use of Schema v3 for making nodes.
- Add input types to the versioned API
- Add additional API functions to get more node packs using only public API