Add alternative domain API configuration (#186)

* Add selection of domain_id

* Get domain id from init options

Author: Acuadros95

rmw_microxrcedds_c/src/rmw_init.c

@@ -163,6 +163,7 @@ rmw_init(
     return RMW_RET_INCORRECT_RMW_IMPLEMENTATION);
   context->instance_id = options->instance_id;
   context->implementation_identifier = eprosima_microxrcedds_identifier;
+  context->options.domain_id = options->domain_id;
 
   rmw_uxrce_init_session_memory(&session_memory, custom_sessions, RMW_UXRCE_MAX_SESSIONS);
   rmw_uxrce_init_static_input_buffer_memory(

rmw_microxrcedds_c/src/rmw_node.c

@@ -134,14 +134,16 @@ rmw_create_node(
   size_t domain_id,
   bool localhost_only)
 {
-  (void)context;
   (void)localhost_only;
   rmw_node_t * rmw_node = NULL;
   if (!name || strlen(name) == 0) {
     RMW_SET_ERROR_MSG("name is null");
   } else if (!namespace_ || strlen(namespace_) == 0) {
     RMW_SET_ERROR_MSG("namespace is null");
   } else {
+    if (domain_id == 0 && context->options.domain_id != 0) {
+      domain_id = context->options.domain_id;
+    }
     rmw_node = create_node(name, namespace_, domain_id, context);
   }
   return rmw_node;