Make Stella compile again with IntelLLVM Compilers (ifx)

[valentin-seitz]

This MR introduces some changes that were necessary to make things compile using the CMake -> ifx toolchain.

The changes are basically:

• Printing the booleans requires to specify the size to be non-zero L0 -> L1. (This is okay for most compilers, ifx is here a bit tighter and follows the standard more strict)
• make namelist-group-object a non-variable length string. Here apparently ifx is also a bit stricter than other compilers

With these changes it works for me in MN5:

---------------------------------
 stella Configuration Summary
---------------------------------

 LAPACK support           : ON
 FFTW support             : ON
 NetCDF support           : ON
 Default real kind        : double
 POSIX support            : OFF
 Use F2003/8 intrinsics   : ON
 Compilation flags        :  -O2 -g
 Build type               : RelWithDebInfo
 Compiler                 : /gpfs/apps/MN5/GPP/ONEAPI/2025.1/compiler/latest/bin/ifx

[100%] Linking Fortran executable stella
Create symbolic link to stella in the directory above COMPILATION/build_cmake
Create symbolic link to stella in the directory above COMPILATION
[100%] Built target stella

[valentin-seitz]

apparently it depends on #233 to go through with the pipelines