Openmpi3

[nieder]

Update for openmpi to v4.1.4, which is a new libN=3
Update deps as necessary.
The current base package openmpi includes both end user binaries and dev-files, which requires setting BuildDependsOnly: false. See #896.

[nieder]

Not sure if my fix for the BDO: false issue is the better way to do it since it might technically allow old openmpi dev library present with new mpicc executable. Maybe instead of using an unversioned openmpi-bin, keep it as openmpi3-bin that will C/R other packages past and future that contain the executables so that packages that need both can be explicit at providing the correct matching pair?