Add GeoJSON endpoint

[grafael]

We would like to have an API like https://stats.storjshare.io/nodes_geo.json but using the GeoJSON format.

AC:

• Refactor nodes_geo.json data to GeoJSON format

Notes:
Example on how to create GeoJSON output: https://gist.github.com/kaloyan-raev/c3dd95f2347a8d49f882b5576508f294

[kaloyan-raev]

Currently, https://stats.storjshare.io/nodes_geo.json reports the coordinates separately for every satellite. It is best to have a single valid GeoJSON object - perhaps, one aggregated for all satellites.

This way, we could load it directly to compatible tools with a direct URL:

https://geojson.io/#data=data:text/x-url,http%3A%2F%2Fstats.storjshare.io%2Fnodes_geo.json

Note, to make the above URL work, we have to ensure that CORS is enabled on https://stats.storjshare.io.