filament_switch_sensor: runout distance, smart and runout gcode

[Zeanon]

Added a runout_distance parameter to filament switch sensors which means that after a filament_switch sensor triggers the printer will print for another x mm of filament (if your sensor sits at the end of a reverse bowden tube)

Filament sensor parameters can now be set via command (If you run a reverse bowden between motion sensor and extruder and retract after a print, there will be a buffer in the bowden which means you intially need a higher detection length than you would need while printint, now you can adjust it on the fly)

Added smart parameter to the sensors:
normally the sensor class uses the idle_timeout sttatus to determine whether the printer is printing, which also tiggers of you just move the toolhead (leading to false positives)
if smart is set to 1, it will use the virtual_sd_card module to determine the state, leading to no false positives but making the sensor not trigger when printing via usb stream

(Of course there are mainsail UI changes for this as well, which I will happily provide if requested :))

[bwnance]

looks really good, thank you! just a couple things.

Could you also clean the PR up? Sorry it's taken us this long to get to it! (Ideally the PR should just have the relevant changes in it, not a bunch of other commits, as it does now)

[Zeanon]

I cleaned up the commit history and I hope I resolved all your comments
I have tested the new merged SET_FILAMENT_SENSOR command on my machine but obviously I havent had time to test it as thouroughly as before, so some feedback would be appreciated :)

[rogerlz]

looking good. please do a new real-world testing and it is ready to be merged

[Zeanon]

For now all commands worked without issues, I guess I'll test it for some days and then report back so we can be sure that everything is definitely working