feat: enable database creation (#141)

proto/greptime/v1/ddl.proto

@@ -70,9 +70,10 @@ message DropTableExpr {
 }
 
 message CreateDatabaseExpr {
-  string database_name = 1;
-  bool create_if_not_exists = 2;
-  map<string, string> options = 3;
+  string catalog_name = 1;
+  string database_name = 2;
+  bool create_if_not_exists = 3;
+  map<string, string> options = 4;
 }
 
 message TruncateTableExpr {

proto/greptime/v1/meta/ddl.proto

@@ -27,6 +27,10 @@ enum DdlTaskType {
     Drop = 1;
 }
 
+message CreateDatabaseTask {
+    CreateDatabaseExpr create_database = 1;
+}
+
 message CreateTableTask {
     CreateTableExpr create_table = 1;
     repeated Partition partitions = 2;
@@ -67,6 +71,7 @@ message DdlTaskRequest {
         DropTableTasks drop_table_tasks = 7;
         AlterTableTasks alter_table_tasks = 8;
         DropDatabaseTask drop_database_task = 9;
+        CreateDatabaseTask create_database_task = 10;
      }
 }