Add a "ray session" like port connector

[ycollet]

In Ray Session, a very useful port is proposed on the GUI:

With this port, it's easy to draw a mono to mono / mono to stereo wire, you just have to click and drag either on the mono area of the connector or on the stereo area.

Can this kind of port be added into Qtrqctor patchbay ?

Ray Session repository: https://github.com/Houston4444/RaySession

[rncbc]

port-groups aren't planned; though you may multi-select several, even non-contiguous, ports in either side and (dis)connect them as in a group.