Support for Creating and Setting NetCDF Attributes in Fortran

[amstokely]

Description:

This PR adds support for creating and writing attributes in NetCDF files from Fortran using the NetCDF C++ API. It simplifies defining attributes, specifying data types, and assigning values, handling global, group-scoped, and variable-specific attributes.

Key Features:

• Attribute Creation: Supports defining attributes in global, group, and variable contexts.
• Data Writing: Enables assigning integer, real, and string values with automatic C/Fortran string conversion.
• Fortran-Friendly Interface: Abstracts low-level C++ API details, ensuring easy integration.

Motivation:

This enhancement provides a streamlined Fortran interface for managing NetCDF attributes, eliminating manual memory handling and C interoperability complexities.

[mgduda]

With #39 merged, can the base branch for this PR be changed to main?

[jim-p-w]

As a general observation, putting every parameter to a function call on it's own line, and the closing ); on it's own line makes the code harder to read. I can't see the entire definition of netcdfPutAtt without scrolling. This seems more legible:

            if (varName) {
                auto var = group->getVar(varName);

                if (netcdfDataType == netCDF::ncString) {
                  var.putAtt(attName, std::string(reinterpret_cast<const char *>(values)));
                } else {
                    var.putAtt( attName, netcdfDataType, len, values);
                }
            } else {
                if (netcdfDataType == netCDF::ncString) {
                  group->putAtt(attName, std::string( reinterpret_cast<const char *>(values)));
                } else {
                    group->putAtt( attName, netcdfDataType, len, values);
                }
            }

[amstokely]

As a general observation, putting every parameter to a function call on it's own line, and the closing ); on it's own line makes the code harder to read. I can't see the entire definition of netcdfPutAtt without scrolling. This seems more legible:

            if (varName) {
                auto var = group->getVar(varName);

                if (netcdfDataType == netCDF::ncString) {
                  var.putAtt(attName, std::string(reinterpret_cast<const char *>(values)));
                } else {
                    var.putAtt( attName, netcdfDataType, len, values);
                }
            } else {
                if (netcdfDataType == netCDF::ncString) {
                  group->putAtt(attName, std::string( reinterpret_cast<const char *>(values)));
                } else {
                    group->putAtt( attName, netcdfDataType, len, values);
                }
            }

I adjusted my linter to only wrap function calls/declarations if they exceed 72 characters.