Bring 3rd party neo4j spatial plugin functionality in-house

[cormander]

As a maintainer of HelloVoter I would like a neo4j plugin that contains just the few procedures we need brought into our own plugin so that we are not tied to waiting on the spatial neo4j plugins release cycle for neo4j upgrades and so we don't carry the functions we don't need that those plugins provide.

This feature is done when:

• The spatial plugins is removed with their procedures replaced by functionality from our own neo4j plugin
• Any procedure that can be done natively with neo4j or with light assistance from JavaScript is ditched in favor of that

Procedures we currently use are: spatial.intersects spatial.withinDistance

[cormander]

NOTE: A simple plugin that does point-in-polygon can be found here: https://github.com/craigtaverner/spatial-3d