Add "serial" to send_gcode's options

[notAnElephant]

It would be very cool if I could send my generated gcode via serial communication (i.e. my 3d printer is connected to my pc via usb, and I want to send it directly the generated gcode). PySerial would be a possible way to solve this

[cilynx]

I'd envision this being configured in the machine JSON similar to Octoprint in kossel.json, just with a new Serial flavor and parameters for baud / data / parity / stop as opposed to IP / Hostname.

Implementation should be fairly straightforward as a third helper in machine.py. What controller are you using? Do you need any sort of setup / handshake / etc. or can you just throw gcode at it? Does any response come back when you send it gcode? If so, what?

[notAnElephant]

I'm using a Marlin-based stock Ender 3 controller. I don't think any handshake is necessary, neither do I need any data from the printer, I just want to communicate with it one-way :)