Use MPI-IO for HDF5 netCDF

https://github.com/mo-marqh/lfric_core/commit/346a1e0f37e97089fa26ec00c234a01dd2d70bc5

demonstrates how MPI-IO can be implemented for reads

this is really beneficial, compared to an all-ranks read serial pattern, which we should not support.

`infrastructure/source/io/lfric_ncdf_file_mod.F90` should be updated to enable this MPI-IO pattern.

Key design question:
* Should there be behaviour switching to allow usage to pick from serial IO && MPI-IO?
* I suspect both patterns are differently useful

Start with infrastructure/source/io/lfric_ncdf_file_mod.F90 and compare it with commit 346a1e0f37e97089fa26ec00c234a01dd2d70bc5, which demonstrates MPI-IO reads. Determine how the existing serial all-ranks read pattern should be replaced and whether serial and MPI-IO behavior need a usage switch. Done means the file supports the selected MPI-IO pattern without requiring the unsupported serial pattern.

Written by the indexing model from the issue text.