DocumentDB input binding - support advanced queries for retrieval

Currently we can only fetch one document, through its ID, at each invocation. It would be great if we could specify a query that would run based on HTTP trigger parameters. Something like this:

SELECT *
FROM volcanoes v
WHERE ST_DISTANCE(v.Location, { 
    "type": "Point", 
    "coordinates": [QPARAM1, QPARAM2] 
    }) < 100 * 1000
AND v.Type = QPARAM3
AND v["Last Known Eruption"] = "Last known eruption from 1800-1899, inclusive"

[mathewc]

This came up in SO recently here: http://stackoverflow.com/questions/40968323/can-i-get-all-the-documents-from-documentdb-in-azure-funtions-without-specifying. We should really expand this binding soon to support pulling in multiple documents.

[brettsam]

Documentation on SqlQuery (which maps to sqlQuery in Functions) can be found here: https://github.com/Azure/azure-webjobs-sdk-extensions/blob/dev/README.md#documentdb