Support for raster data in geoCML Postgres

[TristanDamron]

Is your feature request related to a problem? Please describe.
geoCML Postgres is currently limited in that it cannot store raster datasets.

Describe the solution you'd like
... It'd be really great if we could do that. We would need to figure out how to backup and restore these values with Tabor and gTS as well.

Describe alternatives you've considered
This is kind of an experimental idea... If it turns out to be not viable to do this, we can recommend that users store their raster data in the persistence layer.

[TristanDamron]

This is proving to be very difficult, and maybe not worth doing for v0.3.0. I'm going to move this to Future for now.

If you're a user reading this and are interested in using raster data in geoCML, please import your rasters directly from the persistence layer.