Quality of life improvement

1. there should be a seperate shape or header icon for group input in blender geoemtry nodes so we can find how much inputs we have in our giant node tree.

2. Indicate the unused sockets of group input in N panel in geometry nodes so we can delete them, also there can be an option to purge those unused sockets. (the socket whose input is not used anywhere) it happen when we duplicate node tree and want to keep only some sockets.

3. When the window is vertically very large then it should be divided into two sections (properties, outliner)

there should be an option to divide it in 2-3 columns