feat: Support ComfyUI-Manager for pip version

[ltdrdata]

Manual setup required, yet.

Comfy-Org/ComfyUI-Manager#1737

[christian-byrne]

Can we also ensure the comfyui manager custom node is not imported, except if --disable-manager?

And add to requirements.txt?

[christian-byrne]

I think if --disable-manager is set, we should not import the package at all.

[ltdrdata]

My intention was that --disable-manager should only disable the Manager web service, while keeping other auxiliary features intact.
This includes components like the security scanner, and also allows the Manager to be used as a library.

[ltdrdata]

--disable-manager-ui has been added.
And --disable-manager will prevent importing ComfyUI-Manager.

Now, it is possible to distinguish between disabling ComfyUI-Manager entirely and disabling only the UI of ComfyUI-Manager.

@christian-byrne If the endpoint is blocked using --disable-manager-ui, is it also possible to block ui from the frontend?