Provide access to data from older TMY-3, WGIS, and PVGIS data

[MDKempe]

There are a thousand or so sites from the older data sets that are based on ground based sources in Alaska and elsewhere. I think we should tackle the single site access through NSRDB first. What this would look like is when you call the .get method there could be a boolean pass through that allows for the use of this dataset, with a default setting of true. Then if the selected lat/lon is not in the dataset it would look at the ground based sites that were identified as being outside of all the satellites. The big issue to how to store it on AWS. Maybe the NSRDB people could help.