Fixes determining resource path

[jasonb5]

Adds a function to return a path to the package resources.
The function checks the following locations in order.

1. Under CONDA_PREFIX (checks if path exists or continues)
2. Using pkg_resources
3. Current directory

[jasonb5]

@acordonez After we merge this we can add a patch to the staged recipe.

[lee1043]

@jasonb5 thanks for the PR. The github action build test fails with following message, could you please check?

Traceback:
/usr/share/miniconda/envs/pcmdi_metrics_dev/lib/python3.9/importlib/__init__.py:127: in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
tests/test_resources.py:4: in <module>
    from pcmdi_metrics import resources
E   ModuleNotFoundError: No module named 'pcmdi_metrics'

[jasonb5]

pytest fails while python -m pytest works, I'm guessing it's an issue with sys.path.

@tomvothecoder any idea why this might not be working, the workflow looks identical to xcdat's which works using just pytest.

[tomvothecoder]

@jasonb5 The tests directory was missing an __init__.py file so it was throwing ModuleNotFoundError.

I made a PR fix on your fork (jasonb5#1) to merge to this branch, which should fix the build on this PR.

[jasonb5]

@tomvothecoder Ah totally missed that, makes sense now. thanks

[acordonez]

Thank you Jason! The jupyter notebook demos all ran smoothly for me with this change.