Support $geoNear Pipeline Operator

[charliefoxrf]

Use of the $geoNear pipeline stage results in:

[Error 40324] Unrecognized pipeline stage name: '$geoNear'

It's clear it is not currently supported in de.bwaldvogel.mongo.backend.aggregation.Aggregation.java

Example Mongo query usage:

db.places.aggregate([
   {
     $geoNear: {
        near: { type: "Point", coordinates: [ -73.99279 , 40.719296 ] },
        distanceField: "dist.calculated",
        maxDistance: 2,
        query: { category: "Parks" },
        includeLocs: "dist.location",
        spherical: true
     }
   }
])