Bugfix #2187 main_v10.1 ao_sf

[JohnHalleyGotway]

These changes fix this bug by defining two new NetCDF utility functions, get_var_add_offset_value() and get_var_scale_offset_value(), and then update the vx_data2d_met, vx_data2d_nccf, and vx_data2d_pinterp libraries to call them.

Expected Differences

• Do these changes introduce new tools, command line arguments, or configuration file options? [No]
  
  If yes, please describe:
  

• Do these changes modify the structure of existing or add new output data types (e.g. statistic line types or NetCDF variables)? [No]
  
  If yes, please describe:
  

Pull Request Testing

• Describe testing already performed for these changes:
  
  Ran the plot_data_plane command listed in issue Fix NetCDF library code to process scale_factor and add_offset attributes independently. #2187, and confirm that the values are not properly scaled.

To be clear, here are the range of values before this fix:

DEBUG 4: Data plane information:
DEBUG 4:    plane min: -30620
DEBUG 4:    plane max: 215363

And after the fix:

DEBUG 4: Data plane information:
DEBUG 4:    plane min: -3.062
DEBUG 4:    plane max: 21.5363

Note that these ranges differ by a factor of 10000, which corresponds to the specified scale factor:

HDAY:scale_factor = 0.0001f ;

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  

• Review the code changes.

• Confirm that all GHA tests pass.

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [No]
  None needed.

• Do these changes include sufficient testing updates? [No]
  I chose NOT to add a new test for this case. I decided that it wasn't worth it since this is a custom data file that's still in the process of changing rather than an operational dataset.

• Will this PR result in changes to the test suite? [No]
  
  If yes, describe the new output and/or changes to the existing output:
  

• Please complete this pull request review by [Fri 6/17/22].
  

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[hsoh-u]

I approve. Main differences are conditions to apply add_offset or scale_factor (from both attributes,"add_offset" and "scale_factor", to any attributes.