Average filter before upload to nightscout

[Samhagberth]

It would be very helpful for all that uses libre 3 and loop to have an option to put an average filter on the latest 5 to 10 min bg values before upload to nightscout. This would even out the curve and help with faulty spikes and dips and too high deltas when bg is falling and rising. It would be great if it could be possible to choose a value inbeween 5 and 10 min for example 7 min to find a good compromize between the delay of the bg and the smoothing