Philippe 27/03/2023: ZSOLVER: remove adv_boundaries.f90 and finalize_mnh.f90 (use versions of MNH/ instead)

Philippe 21/03/2023: fix: zsolver_inv.f90: remove old FFT module (does not exist anymore, forgotten to remove before in repository)

(work in progress, compilation OK, runs MNH CPU+GPU OK, runs ZSOLVER CPU-only OK)

Juan 20/03/2023:ZSOLVER/turb_hor_uv.f90, Bypass Nvhpc BUG <->  zflx partially present/error 700: Illegal address during kernel execution <-> remove "acc loop ..." & replace DO CONCURRENT -> mnh_do_conccurent , better perf

Merge remote-tracking branch 'refs/remotes/origin/MNH-55X-dev-OPENACC-FFT' into MNH-55X-dev-OPENACC-FFT

Juan 17/03/2023:ZSOLVER/multigrid.f90,finalize_mnh.f90, Managed output in timing.txt , verbose=1/residual , verbose=10/timing by level, verbose=100/timing by iteration

Juan 16/03/2023:ZSOLVER/p_abs.f90, replace DO CONCURRENT -> mnh_do_conccurent , better perf with acc parallel

Juan 16/03/2023:ZSOLVER/discretisation.f90, Little OpenAcc Typo detected with NVHPC, missing & <-> continuation line at end of acc parallel

Juan 16/03/2023:ZSOLVER/communication.f90, Cray OPENACC Opt, pass ztab* by args + dim in boundary_mnh/_dim

Juan 16/03/2023:ZSOLVER/discretisation.f90, Cray OPENACC Opt, pass ztab* by args + dim in calculate_residual_mnh/_dim

Juan 16/03/2023:ZSOLVER/contrav.f90, Cray OPENACC Opt, pass ztab* by args + dim in contrav_device/_dim

Juan 16/03/2023:ZSOLVER/discretisation.f90, Cray OPENACC Opt, pass ztab* by args + dim in apply_mnh/_dim

Juan&Naima 16/03/2023:MNH/advec_weno_k_3_aux.f90,bl89.f90,ice4_sedimentation_split.f90, Cray OpenACC opt , add present_cr to avoid recurrence in kernels

Juan 15/03/2023:ZSOLVER/discretisation.f90, Cray OPENACC Opt, pass ztab* by args + dim in loop_over_grid_jacobi_mnh/_dim

Juan 15/03/2023:ZSOLVER/communication.f90.f90, Cray OPENACC Opt, pass ztab_halo* by args + dim in haloswap_mnh

Philippe 13/03/2023: OpenACC: FFT: transform some work vectors into scalars + add privates for them (solve an OpenACC bug)

Juan 10/03/2023:ZSOLVER/discretisation.f90, Cray OPENACC Opt, pass ZTAB by arg + dims in apply_tridiag_solve_mnh_allT