Philippe 18/09/2023: FLAT_INV: fix for NOOPENACC (deallocate ZBAND_YT and ZBAND_YRT only if allocated)

Philippe 12/09/2023: remove key MNH_PGI (not useful anymore, was to workaround an bug in very old version of PGI compiler)

Philippe 29/08/2023: OpenACC: work around for a problem with NVHPC 23.7 (not present in older versions)

(cherry picked from commit ce39d7dc)

Philippe 29/08/2023: OpenACC: work around for a problem with NVHPC 23.7 (not present in older versions)

Philippe 25/07/2023: transfer ZSOLVER/ppm.f90 to MNH/ + adapt it. This gives better performance on GPUs.

Philippe 17/07/2023: FFT: invert loops for better performance and to allow correct parallelization by NVHPC OpenACC

Philippe 26/06/2023: ice4_sedimentation_split: remove a DO CONCURRENT because of a reduction in loop (wrong reults with NVHPC 23.5)

(cherry picked from commit ad799fd0)

(cherry picked from commit 18a466fd)

Philippe 26/06/2023: ice4_sedimentation_split: remove a DO CONCURRENT because of a reduction in loop (wrong reults with NVHPC 23.5)

(cherry picked from commit 9c064dd7)

Juan 19/06/2023:rain_ice_sedimentation_split.f90, Again SegFault at execition with CRAY ftn -> deactivate mnh_expand_array for CRAY ftn !!!

Juan 19/06/2023:rain_ice_sedimentation_split.f90, For pref PB with nvhpc , reintroduce mnh_expand_array & MNH_MEM_GET(ZRTMIN...) + replace data create -> present

Juan 16/06/2023:MNH/* , For Nvhpc , remove duplicate "!$acc loop" introduced by use of mnh_do_conncurrent

Juan 16/06/2023:rain_ice_sedimentation_split.f90, Strange Cray SegFault -> replace mnh_do_concurrent -> array syntax

Juan 13/06/2023:ice4_sedimentation_split.f90 , For gfortran+openacc ,replace DO CONCURRENT -> mnh_do_concurrent

Juan 13/02/2023: MNH modif for compile with sourceryg/2022.09-7-orig+OPENACC + optimization for CRAY ftn

Philippe 22/05/2023: FFT: deduplicate FAST_TRANSPOSE, FAST_SUBSTITUTION_2D, FAST_SUBSTITUTION_3D and FAST_SPREAD

Philippe 22/05/2023: FFT: FFT991: pass argument PWORK as a 3D array (no need to use an intermediary 1D pointer at this level)