Simple filmanet runout sensor housing using a microswitch

This sensor housing is designed to hold a micro limit switch that is approx 6.5mm wide, 10.5mm, and up to 23mm long. I don't have a link to the switch I used, but I'd think it's a fairly standard size. Maybe it's not - let me know!

The switch should have a rounded end of the paddle, otherwise retracts will probably scratch the filament and a filament change command could jam the filament over the paddle, which would probably just push the sensor out of the ptfe tube (if installed).

I have a direct drive, but as I was writing this I thought about longer Bowden setups... this sensor would need to go upstream of the extruder motor. I don't have any mounting solutions, but it should still work fine.

I use this such that the switch is connected to the Raspberry Pi running OctoPrint, and have the [Filament Sensor Simplified](https://github.com/luckyx182/Filament_sensor_simplified) plugin installed to manage the signal.

This sensor also doesn't have fancy features like jam detecti