feat: interal type for row protocol, and multi row deletes (#80)

proto/greptime/v1/database.proto

@@ -40,7 +40,7 @@ message GreptimeRequest {
     DdlRequest ddl = 4;
     DeleteRequests deletes = 5;
     RowInsertRequests row_inserts = 6;
-    RowDeleteRequest row_delete = 7;
+    RowDeleteRequests row_deletes = 7;
   }
 }
 
@@ -109,6 +109,10 @@ message RowInsertRequest {
   uint32 region_number = 3;
 }
 
+message RowDeleteRequests {
+  repeated RowDeleteRequest deletes = 1;
+}
+
 message RowDeleteRequest {
   // The table name to delete from. Catalog name and schema name are in the
   // `RequestHeader`.