Make it easier to warn users about spatial reference mismatches or SRS being unset

[phargogh]

In the interest of consistency across pygeoprocessing, it would be great if we had some way to warn users about problems with their spatial references, specifically:

• Whether a file's spatial reference is unset (as is the case with some GDAL formats that do not support georeferencing)
• Whether two input files that should overlap really do overlap
• Whether two input files that should have the same SRS really do have the same SRS

Maybe this could be a function, maybe a decorator for a function, maybe something else.

This came up in #338 and was discussed in our software team meeting 2023-08-29.