Data Extension for postgis use for documentation and possibly tests

[robe]

I'm going to break this out into separate steps.

We talked about having these on IRC so that our documentation can just reference them.

This one would be called: postgis_sample_data

and would have sample tables for geometry / geography

These can be an additional steps in the repo and we can dispense with upgrade paths and would not by default build them. Maybe eventually we can have a ./configure --with-sample-data or some such thing to make it easier.

So would be:

To build would be something like

make postgis_sample_data

CREATE EXTENSION postgis_sample_data;

[robe]

Milestone renamed