add MPI_Init and MPI_Finalize PMPI wrappers

[MichaelBrim]

Description

Adds a configure option for --enable-mpi-mount, which adds PMPI wrappers for MPI_Init and MPI_Finalize that call unifycr_mount and unifycr_unmount respectively.

Fortran support is also included.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the UnifyCR code style requirements.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• All commit messages are properly formatted.

[MichaelBrim]

I just pushed support for interception on Fortran too. I tested on Summitdev, so this should work on all OpenMPI based platforms. We should find a system where we can test MPICH too.

We should still probably have an explicit Fortran interface for UnifyCR calls like mount/unmount, but this works now for existing Fortran MPI apps.

[adammoody]

Thanks @MichaelBrim !