GSI2DART: replaced certain mpi functions with DART abstracted versions

[tyiop794]

Description:

I replaced the MPI functions used in GSI2DART with the variants found in mpi_utilities_mod.f90. While this version does compile, I still am not sure whether it works as intended, and I'm not sure how to test.

Fixes issue

fixes #633

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Documentation changes needed?

• My change requires a change to the documentation.
  • I have updated the documentation accordingly.

Tests

Please describe any tests you ran to verify your changes.
This version actually compiles with GNU Fortran versions above 11.2.0 (tested with version 15.2.1). However, I'm not sure how to test whether the compiled binary produces the correct output.

Checklist for merging

• Updated changelog entry
• Documentation updated
• Update conf.py

Checklist for release

• Merge into main
• Create release from the main branch with appropriate tag
• Delete feature-branch

Testing Datasets

• Dataset needed for testing available upon request
• Dataset download instructions included
• No dataset needed

[hkershaw-brown]

@tyiop794 thanks for taking a look at this. Currently we do not have GSI input to test this, so I'm closing this pull request for now.