fix missing dll path for os.add_dll_directory + print debug info

Some important dlls were missing in initDLL() (the function that tries to add the folders containing the shared libraries of the dependencies of all the python modules):

• intel compiler runtime (required by MKL),
• MUMPS.

I have added these 2 folders in the initDLL loop although I think it would be much easier to add all the folders from the PATH.

I have also printed some debug lines while looking for the folders in the PATH:

D:\dev\amfe-solvers>run.py heat\tests\basics\dirichletx.py
[initDLL] looking for tbb
[initDLL]       os.add_dll_directory("C:\Program Files (x86)\Intel\oneAPI\tbb\latest\redist\intel64\vc_mt\")
[initDLL] looking for mkl
[initDLL]       os.add_dll_directory("C:\Program Files (x86)\Intel\oneAPI\mkl\latest\redist\intel64")
[initDLL] looking for vtk
[initDLL]       os.add_dll_directory("C:\local\VTK\bin")
[initDLL] looking for mumps
[initDLL]       os.add_dll_directory("C:\local\MUMPS\bin")
[initDLL] looking for compiler
[initDLL]       os.add_dll_directory("C:\Program Files (x86)\Intel\oneAPI\compiler\latest\windows\redist\intel64_win\compiler")
[findbins] looking for win/release libs
[findbins] loading  D:\dev\amfe-solvers\build\bin\Release\fwkw.py
* OMP environment:
    OMP_NUM_THREADS = 1
* MKL environment:
    MKL_INTERFACE_LAYER = LP64
    MKL_THREADING_LAYER = TBB
...

I have added an underscore in the display of OMPvariables so that PROMPT or INTEL_COMPILER_* are not displayed anymore.