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/simple_model.c

@@ -174,8 +174,8 @@ modelRun(struct model_config setup, MPI_Comm comm)
         varDesc[varIdx].start = start;
         varDesc[varIdx].chunkSize = chunkSize;
         varDesc[varIdx].partDesc = xt_idxstripes_new(&(struct Xt_stripe){ .start = start, .nstrides = chunkSize, .stride = 1 }, 1);
-      partDescriptionSet:;
       }
+    partDescriptionSet:;
 #endif
       varDesc[varIdx].code = GRIB_USERDEF + (int) varIdx;
       vlistDefVarCode(vlistID, varDesc[varIdx].id, varDesc[varIdx].code);