Only makes sense (models and docs) after #2454.

Summary is that by adding a simple file like the below to each PSIthon/CTest directory (dir in tests/ that has an input.dat or input.py), we can run the test additionally through pytest. Read the docs to see why this is a good thing and more details on how to compose the file.

from addons import *

@ctest_labeler("quick;ci;cas;properties;cart;noc1")
def test_ci_property():
    ctest_runner(__file__, ["grid.dat"])

A few dozen have been done, but filling in all 500 is suitable for distributing the workload.