Add support for geo coordinates and geopoints to website

[amoeba]

[amoeba]

The task here is to expand jsonld_to_mustache with more functions like this:

https://github.com/ropenscilabs/dataspice/blob/341ae3b259cd9292f4a8c51e280cf3059078f174/R/jsonld_to_mustache.R#L23-L28

[amoeba]

Plus: What other spatial stuff should we easily support? wkt?

[khondula]

geojson? kml/kmz? Named locations?

For support here, do you mean for creating json and map display, or for extracting from data with prep functions to get the coverage info in the first place? Would be nice to be able to "prep_spatialcoverage" from a geotiff, sf, or spatial*dataframes object...

[amoeba]

Good question -- I wasn't clear! The specific part of this Issue is what we support display for, which is dependent on what's serialized from write_spice(). I renamed the Issue to reflect the much more narrow scope. At this point I was just thinking of supporting points and polygons.

I think your idea about helping the user import spatial coverage information from geojson/kml/etc makes a ton of sense. If we don't already have that penciled out we should.