Merge set get into one block

[guzuligo]

I was redirected to this when I opened an issue requesting for the same thing as this amazing extension
comfyanonymous/ComfyUI#1129 (comment)

I think if instead of having a set/get blocks, the block appears just like a reroute block with a variable. When the input is used, the set is activated. If output is used, the get is activated. This way, you could even use this block as a reroute block at the same time.

Glad to have landed on this extension 👍