Consolidation with CDI-PIO (develop)

Generally, this is !11 (merged) rebased onto the develop branch.

This is the first develop-based version accepted by the Buildbot of ICON: https://buildbot.dkrz.de/grid?branch=m300488/cdi-pio-2-integration

tests/deco2d_model.c

@@ -227,7 +227,7 @@ modelRun(struct model_config setup, MPI_Comm comm)
       vlistDefVarDatatype(vlistID, varDesc[varIdx].id, setup.datatype);
     }
 
-  taxisID = taxisCreate(TAXIS_ABSOLUTE);
+  taxisID = taxisCreate(setup.taxistype);
   vlistDefTaxis(vlistID, taxisID);
 
   for (tfID = 0; tfID < ntfiles; tfID++)