Add ComfyUI-Impact-Pack and ComfyUI-Impact-Subpack

[fofr]

Follow up to #20

• Uses a forked version of Impact Pack (see https://github.com/fofr/ComfyUI-Impact-Pack):
  • prevents any automatic installation
  • loads the impact_subpack as a submodule
  • includes a default config
  • prevents automatic deletion of the impact_subpack directory if .git is missing
• Adds SAM and Ultralytics weights
• Automatically downloads Ultralytics weights if a UltralyticsDetectorBox node is used

Closes #13

[fofr]

@digitaljohn I've pushed this branch to this model:
https://replicate.com/fofr/comfyui-prototype

If you want to give it a go and see if there are any problems.

[fofr]

My basic test has worked, using one of the workflows from the tutorials repo:
https://replicate.com/p/iutngslbdyoalv55ew56ei42yy