[Feature Request] Chip based groups / general group update

I think it would be useful to have a new ChipNode Group with a custom amount of IO 'reroute' nodes, and a customizable display based on the contents of the group. Being able to build new 'chips' within the UI would be quite powerful, and would help clean up routing, as well as simplifying re-useable groups in a way that Node Templates doesn't quite reach in its current form.

As an example a txt2img chip could look something like this.

Being able to expand and collapse to edit the contents would also be helpful, although the group hierarchy issue (#477 ) would probably need to be fixed as well.

Having a way to lock the contents of the group, so that if it expands over other nodes it doesn't automatically include them into the group, which is a slight issue with the current implementation would also be good. Auto selecting the groups contents when you select a group too.

For another reference in regards to ChipNodes - similar functionality to the following logic gate app is essentially what I mean. https://github.com/SebLague/Digital-Logic-Sim