Reproducible summation of floating point arrays

Array sums are reproducible whichever

• the array ordering is
• the number of processors is
• the number of threads is

To use classic sums one can use the --no-reproducible-sums option the default behavior is reproducible summations.

Also merged feature/new_mpi_com_pugs which is used for code coupling

enabled an automatic merge when the pipeline for e365d69a succeeds

merged

mentioned in commit 937c5bae