Issue94 mgrs tile code to lat lon utility

[david-inglish]

Initial implementation of utility to convert from MGRS tile codes to lat/lon bounding box.

[collinss-jpl]

Branch looks good, had some minor findings and suggestions for improvements, but I'm most concerned about making sure the unit test runs from within the container. See my comment on the skipIf decorator line.

[collinss-jpl]

Please co-locate this with the rest of the imports at the top of the module

[david-inglish]

I think I need more input on this. I moved this into the @skipIf scope because otherwise it will raise an exception in get_geographic_boundaries_from_mgrs_tile() when it tries to import osgeo if it doesn't exist. I don't think that we want to suppress the import exception in get_geographic_boundaries_from_mgrs_tile().

One thought is that I can add try/except to the import in test_metadata_utils.py:

try:
    # If mgrs, osr, or gdal are not available for import, this will raise an exception
    from opera.util.metadata_utils import get_geographic_boundaries_from_mgrs_tile
except:
    pass

Am I missing a more elegant solution for this?

Here is the exception raised if moved out of the skipIf scope:

Traceback:
../../../.conda/envs/opera/lib/python3.8/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
src/opera/test/util/test_metadata_utils.py:15: in <module>
    from opera.util.metadata_utils import get_geographic_boundaries_from_mgrs_tile
src/opera/util/metadata_utils.py:13: in <module>
    from osgeo import gdal
E   ModuleNotFoundError: No module named 'osgeo'

[collinss-jpl]

Good point, I left out a piece of the puzzle here, which is adding an import check in metadata_utils.py to swap out the osr module with a mock implementation of the osr module if from osgeo import osr fails (seems like gdal is not getting used in metadata_utils.py currently). However, I'm fine with deferring this to a later PR.

[collinss-jpl]

Updates all look great, thanks for the quick turnaround!