* New process-control RPC feature in clixon-lib.yang to manage processes

* This is an alternative to manage a clixon daemon via sudtemd, containerd or other
  * One important special case is starting the clixon-restconf daemon internally
  * This is how it works:
    * Register a process via `clixon_process_register(h, name, namespace, argv, argc)`
    * Use process-control RPC defined in clixon-lib.yang to start/stop/restart or query status on that process
  * Example code in the main example

yang/clixon/clixon-lib@2020-12-08.yang

@@ -164,14 +164,10 @@ module clixon-lib {
 		description
 		    "One of the strings 'start', 'stop', 'restart', or 'status'.";
 	    }
-	    leaf namespace {
-		type string;
-		description
-		    "Network namespace.";
-	    }
 	}
 	output {
 	    leaf status {
+		description "For status: is the process running?";
 		type boolean;
 	    }
 	}