Implement robust GeoJSON validation

[jreiberkyle]

The python SDK receives geometry information from the user as GeoJSON in the form of files, strings, and python objects. From there, the SDK checks that the GeoJSON is valid and extracts the geometries. Validation should check the GeoJSON schema and geometries are valid and give useful error messages.

Currently, the geojson module only supports single-geometry GeoJSON types and does not validate the GeoJSON schema. Implement a robust GeoJSON linter that checks the schema as well as the geometry, supports all GeoJSON types, supports files, strings, and python objects as inputs, and provides useful error messages upon validation failure.