add CreateTopic API

weed/pb/mq.proto

@@ -26,6 +26,8 @@ service SeaweedMessaging {
     // control plane for topic partitions
     rpc LookupTopicBrokers (LookupTopicBrokersRequest) returns (LookupTopicBrokersResponse) {
     }
+    rpc CreateTopic (CreateTopicRequest) returns (CreateTopicResponse) {
+    }
     // a pub client will call this to get the topic partitions assignment
     rpc RequestTopicPartitions (RequestTopicPartitionsRequest) returns (RequestTopicPartitionsResponse) {
     }
@@ -128,6 +130,13 @@ message ConnectToBalancerRequest {
 message ConnectToBalancerResponse {
 }
 //////////////////////////////////////////////////
+message CreateTopicRequest {
+    Topic topic = 1;
+    int32 partition_count = 2;
+}
+message CreateTopicResponse {
+    repeated BrokerPartitionAssignment broker_partition_assignments = 2;
+}
 message LookupTopicBrokersRequest {
     Topic topic = 1;
     bool is_for_publish = 2;