Philippe 01/02/2022: OpenACC: use MNH_ALLOCATE_FLAT and MNH_RELEASE_FLAT instead of old allocate/release procedures

Philippe 31/01/2022: OpenACC: possibility to allocate arrays by providing dimension sizes (+ doctor norm improvements)

Philippe 31/01/2022: OpenACC: create IT1DFLAT buffer that can be used for any size and shape arrays (integer)

Philippe 26/01/2022: OpenACC: workaround CCE compiler problem: add list of dimensions in array copies in a kernels region

Philippe 26/01/2022: OpenACC: workaround CCE compiler problem: put character array outside of kernels region

Philippe 26/01/2022: OpenACC: workaround CCE compiler problem: add intermediate variable for some scalar pointers in kernels regions

Philippe 18/01/2022: OpenACC: store result of LNORTH_ll() and co in logicals to be used in kernels regions + do also this for HLBCX and co
The later is a workaround for a Cray compiler bug (CCE 13.0.0)