Rename visionlouisville to hatch

* Fix any preexisting tests, to make sure they still work afterward
* Enable the migrations to be run as part of the tests
* Rename all relevant folders
* Add `hatch` to `INSTALLED_APPS`
* Recreate a `visionlouisville` app (with just empty `__init__` and `models` modules) and copy migrations back over to it (South still expects these to be visionlouisville migrations)
* Create an initial migration in `hatch` that depends on the last `visionlouisville` migration and renames all the model tables