Add location cluster centroid latitude and longitude features

[jenniferfedor]

This PR adds to the phone locations Doryab provider features for the latitude and longitude of the centroid of each of the first, second, and third most significant location clusters. The centroid of each cluster is computed as the weighted mean of the individual coordinates assigned to the cluster. These are intended to be companion features for the timeattop1location, timeattop2location, and timeattop3location features that could be used for further processing or analysis (e.g., as inputs to Google Maps Geocoding API). Note that processed data containing these features are no longer deidentified.

To process these features, in the config file the INCLUDE_COORDINATES parameter in the must be toggled to True and the respective timeattop[n]location feature must be included in the FEATURES array.