Select proxy address by closest available geo

[cweems]

Create function that splits out the area code and associates it with a lat-lon. This CSV maps are codes to lat-lon coordinates: https://github.com/ravisorg/Area-Code-Geolocation-Database/blob/master/us-area-code-geo.csv

Use a library like geolib to get the distance between the customer's number and potential proxy addresses. Sort proxy address candidates by distance and then eliminate ones that are already bound.

Update readme with any geo constraints based on this implementation.