Add weighted average to satellite data extraction to reduce nulls

[ChristinaLast]

Temporal weighting

• [x] adding parameter lookback_n to keep looking back into satellites to get the n number of historic satellite pixel values from sensor date.
• [x] check if a satellite returns a value and add an attempt_counter
• [x] if find a value add one to lookback_counter and continue looking back until lookback_counter == lookback_n
• [x] take a weighted average of all the 5 returned pixel values, multiplying the weight by 1 / attempt_counter == weight

Spatial weighting

• [x] have a parameter search_proximity that extends the search radius of the getRegion() call.
• [x] take the IDW average of the pixel values based on the proximity to the sensor location