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/pio_write.c

@@ -28,7 +28,7 @@
 
 static const struct model_config default_setup
 #ifdef __cplusplus
-    = { 12, 6, 3, 5, 5, CDI_FILETYPE_GRB, CDI_DATATYPE_PACK24, 1, 0, "grb" };
+    = { 12, 6, 3, 5, 5, FILETYPE_GRB, CDI_DATATYPE_PACK24, 1, 0, "grb" };
 #else
     = {
         .nlon = 12,