Implementation of STOP exchange

This implements the STOP.request/indication for all 3 transport mechanisms, the VNF will send the STOP.request to the PNF, indicating it will disconnect, and await a STOP.indication from the PNF

The WLS VNF is reworked to be able to start before the PNF, by calling call rte_eal_init and rte_dev_probe to determine if dpdk has been initialized properly, before calling rte_eal_init in the intended process when it is appropriate to do so

executables/nr-softmodem.c

@@ -716,6 +716,8 @@ int main( int argc, char **argv ) {
   itti_wait_tasks_end(NULL);
   printf("Returned from ITTI signal handler\n");
 
+  nfapi_stop_l1();
+
   if (RC.nb_nr_L1_inst > 0 || RC.nb_RU > 0)
     stop_L1(0);