[DevOps]: Update the structure of supporting files to reduce re-sorting and bloat in pyproject.toml

[tomvothecoder]

Is your feature request related to a problem?

• Related to [DevOps]: CDAT Migration: Replace setup.py with pyproject.toml for modern Python packaging #895 -- replaces setup.py with pyproject.toml

There are many supporting files that e3sm_diags requires including .cfg, .rgb, .nc, etc. that needs to be installed alongside e3sm_diags. The setup.py file includes logic to move these files around to the correct location in order for them to be correctly installed via python -m pip install ..

Describe the solution you'd like

@xylar suggests that the e3sm_diags data files should have a similar structure internally to what it puts in share/e3sm_diags (related comment). That way the pyproject.toml isn't nearly as bloated and there is less resorting of files required upon installing the package.

Describe alternatives you've considered

No response

Additional context

No response