change all fms2 fileobj instances to fms2io_fileobj

[mcallic2]

Description
The changes in this pr include changing all instances of the FmsNetcdfFile_t types named fileobj to fms2io_fileobj

Fixes # (issue)

How Has This Been Tested?
autotools with gcc/13.1.0 , netcdf/4.9.2, mpich/4.1.2 , hdf5/1.14.1-2 , libyaml/0.2.5

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules
• New check tests, if applicable, are included
• make distcheck passes