Feature 342 write mpr file

[CPKalb]

Pull Request Testing

• Describe testing already performed for these changes:
  
  Ran the use cases to test that they write output MPR files correctly

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  
  Check out the following branches of METplus, METcalcpy, METplotpy, and METdataio
  feature_1344_stratosphere_bias of METplus
  feature_342_write_mpr_file METcalcpy
  develop branch of METplotpy
  bugfix_247_readnc_no_lon METdataio

Run 1 use cases, s2s/UserScript_fcstGFS_obsERA_StratospherePolar.conf. Verify that that the StratospherePolar use case produces a bunch of MPR files as intermediate output. They will be located in OUTPUT_BASE/UserScript_fcstGFS_obsERA_StratospherePolar/mpr

The documentation should be located at docs/Users_Guide/write_mpr.rst

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [Yes or No]
  Yes

• Do these changes include sufficient testing updates? [Yes or No]
  Tests for the script will be added under issue 358

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

• Please complete this pull request review by [Fill in date].
  
  02/13/2024

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