move common code file in common directory

remove several unused files
remove mem_block_t that is never used in a different way than a simple heap buffer
move up IP address type and remove duplications of the same struct declaration

nfapi/open-nFAPI/nfapi/public_inc/fapi_nr_ue_interface.h

@@ -19,7 +19,7 @@
 #include <pthread.h>
 
 #include "stddef.h"
-#include "platform_types.h"
+#include "common/platform_types.h"
 #include "fapi_nr_ue_constants.h"
 #include "PHY/impl_defs_top.h"
 #include "PHY/impl_defs_nr.h"

nfapi/open-nFAPI/pnf/src/pnf.c

@@ -31,7 +31,7 @@
 #include "pnf.h"
 
 # if 1 // for hard-code (remove later)
-#include "COMMON/platform_types.h"
+#include "common/platform_types.h"
 #include "common/platform_constants.h"
 #include "common/ran_context.h"