Show cable priority, and priority re-order contextual menu

[AlexMitchellMus]

PD sets the execution order of multiple outputs based on the order in which the patch cables are added.
For specific execution order, it is recommended to use trigger. This FR is not to replace trigger but to allow the user to see what is happening with multiple-connections, and if simple enough to use this feature.

It would be good to:

• Show the order of execution on the cable
• Enable a user to change the order of a specific cable, without having to reconnect it. (changing priority would also reconnect the cables internally, so such ordering would automatically be compatible with PD-Vanilla, however the execution order is not shown in PD-Vanilla)

Showing execution order:

Add to the node / cable contextual menu Priority Up / Down item:

Discussion from Discord with abreubacelar:

so for example say we have 4 connections and the current order is
2 1 4 3
changing the first cable priority up would give
1 2 4 3,
then moving the same cable down 3 times
2 1 4 3
3 1 4 2
4 1 3 2
but if i ask it to go high priority it would change directly to
1 2 4 3
you could of course change any cable, so if i select the second and ask it to go lowest priority it would change to
1 4 3 2

Example of trigger & cable priority tags doing same execution order: