nr rlc: first commit

Initial implementation.

nr_rlc/nr_rlc_oai_api.c will need some clean rewrite at some point.

More testing is also needed.

targets/TEST/PDCP/with_rlc/test_pdcp_rlc.c

@@ -226,7 +226,7 @@ int main(int argc, char **argv)
   mac_xface = malloc(sizeof(MAC_xface));
   Mac_rlc_xface = (MAC_RLC_XFACE*)malloc16(sizeof(MAC_RLC_XFACE));
 
-  rlc_module_init ();
+  rlc_module_init (1);
   pdcp_module_init();
   logInit();