DMX support

[paradajz]

I am considering adding the DMX support to OpenDeck boards. This thread will be used for all the updates around this, but also for any feature requests or suggestions regarding the use case of this. At the moment I don't really have any concrete plans about this, but I do have some ideas:

1. I thought about having the OpenDeck board in dual mode - plugging it on PC would register both as MIDI and DMX device. The DMX device mode is actually just virtual COM port which should be compatible with most popular DMX control apps (preferably the multiplatform ones). Sending data from those apps to OpenDeck board would result in data being transferred to XLR output.

2. The ability to assign DMX channels and values to components on OpenDeck board through the existing web interface.

Comments welcome!