Ensuring Fortran modules do not end up at `GCCcore`

[ocaisa]

There's currently no check to ensure that Fortran modules do not end up at GCCcore level. It's a tricky one to catch as the builds have no problem. Can we implement something in CI to help with this?

Fixes are tedious and quite intrusive: see #19283

[branfosj]

See my (limited) notes in easybuilders/easybuild-framework#4203

[ocaisa]

Perhaps this is something we can fix at a framework level by shadowing gfortran with something that prints something useful and exits with an error.

[ocaisa]

Wrapping the compiler is perhaps too aggressive, I think I probably agree with @branfosj that we should search for .mod files.

[branfosj]

See easybuilders/easybuild-framework#4389

[ocaisa]

Fix is in for 5.0