Enable AIP recovery, fix testing fixtures

Add AIP recovery constants to Spaces that support it.

Update check that ensures only one AIP recovery location is associated with a Pipeline and move it to the clean() function.

Add tests for this.  Fix fixtures so that initial_data.json (renamed to base.json) is actually loaded.
It's the version of Django I ran into the problem in, so I know to revisit and remove the hack later.  Updated to be clearer.