Sweep requirements, ATS tests, and executable tests for alignment

[jyutzler]

We need to make sure everything is aligned.

[jyutzler]

/base/core/spatial_ref_sys/data_values_required is unfortunately positioned. There should be individual requirements under the tiles and features parts of the standard. Since attributes are inherently non-spatial, their SRSs can be null. This makes the ATS invalid as written. Fortunately or not, the ETS was not using the test prescribed in the ATS. I will update the ATS to match the ETS.

[jyutzler]

Today the SWG approved these changes to the ATS