Consider sorting results by geographic relevancy

[caseycesari]

We would have to perform the geographic operations on our end, but I think it could result in more relevant results on the first page if we sort results by how much of the result bounding box is within the AoI. Often, nationwide results are shown on the first page, which seems less relevant.

There may be some issues with results that have multiple bounding boxes. Some of these bounding boxes appear to contain bad coordinates.

[rajadain]

We should consider sorting results first by distance from map center, and then by size, so the smallest closest things are on top.

[rajadain]

Some of this is addressed by #2314. It should be noted that CINERGI and HydroShare results are sorted by some internal metric of relevance, and WDC / CUAHSI results are sorted by recency. During development, we search for overly simplistic terms like "water" leading to the large quantity of seemingly irrelevant results, but for the purposes of the app I think the sorting we have right now works correctly.