Add support for extra custom node path.

[realno]

This PR allows users to load custom nodes from multiple directories, similar to how extra model paths work in ComfyUI.

For example, the users can keep all the custom nodes on a shared/portable drive and mount it to different computers or systems (Win & Linux).

Added support for loading custom nodes from multiple directories through a YAML configuration file called extra_custom_node_paths.yaml. This is useful when you want to:

Benefit:

Organize custom nodes in different locations
Share custom nodes between multiple ComfyUI installations
Keep custom nodes separate from the main ComfyUI directory

How to use:

Create a file called extra_custom_node_paths.yaml in ComfyUI root directory:

comfyui:
base_path: /path/to/base1
ComfyUI will try to load custom nodes from "/path/to/base1/custom_nodes" in addition to the default path.

[webfiltered]

The documentation should probably have some info on how this is handled. That is, if you have a copy of a node pack in two directories - what happens, exactly?

[comfyanonymous]

You can already use the extra_model_paths.yaml for this

[realno]

You can already use the extra_model_paths.yaml for this

Thanks for pointing this out, let me look more into existing functionality.

[realno]

Confirmed using existing model path yaml works too, closing the PR.