Adding version check for NetCDF fortran library

Currently PIO only supports checking the version of the NetCDF C library.

We do not check the version of the NetCDF Fortran library and hence also do not perform any minimum version checks on it.

AFAICT, the NetCDF fortran library provides two ways to find the version of the library (no compile-time option),

* Using nf-config (--version option)
* Using NF_INQ_LIBVERS() function

The current cmake scripts find the version of the NetCDF C library by parsing the version string in netcdf_meta.h (I don't think a similar option exists for the Fortran library)