expose geospatial queries via CIMI

[konstan]

Pointers.

• ES support for GeoJSON https://www.elastic.co/guide/en/elasticsearch/reference/current/geo-queries.html (for data types see https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-types.html#_geo_datatypes)
• GeoJSON http://geojson.org/ and https://tools.ietf.org/html/rfc7946
• GeoJSON use in OGC http://docs.opengeospatial.org/is/14-055r2/14-055r2.html
• Example of the "free query" from https://scihub.copernicus.eu/dhus/#/home

(footprint:"Intersects(POLYGON((4.753543767569296 45.80446751452055,6.843395266424191 45.80446751452055,6.843395266424191 46.59905873188191,4.753543767569296 46.59905873188191,4.753543767569296 45.80446751452055)))" ) 
AND ( beginPosition:[2018-02-25T00:00:00.000Z TO 2018-02-27T23:59:59.999Z] 
AND endPosition:[2018-02-25T00:00:00.000Z TO 2018-02-27T23:59:59.999Z] ) 
AND (platformname:Sentinel-2 AND producttype:S2MSI1C)

[konstan]

The last example query turns out to be WTK https://en.wikipedia.org/wiki/Well-known_text (thanks @loomis).