Add some sample smoothing for the sensor class

[dimembermatt]

Currently, the sensor classes grab data from the ADC and update an internal variable that can later be extracted for MPPT. This typically is exposed to a lot of variance temporally.

We should smooth out our signal input by holding a buffer of N samples size, and taking the moving average of that buffer whenever we get a new output from the sensor.

This needs to be applied for both the current and voltage sensors.

[dimembermatt]

See moving average (the easy implementation) and kalman filters (a more advanced implementation).

[dimembermatt]

Reference #26 for a mockup of the SMAFilter class.

[dimembermatt]

• [x] SMAFilter
• [x] Exponential Moving Average Filter
• [x] Moving Median filter
• [x] Kalman filter

[dimembermatt]

Add tests for EMAA and Kalman filter.

[dimembermatt]

27 Merged.

[dimembermatt]

Nevermind, forgot we need some tests.