feat: region storage path (#102)

proto/greptime/v1/region/server.proto

@@ -85,13 +85,10 @@ message CreateRequest {
   repeated uint32 primary_key = 4;
   // Create region if not exists.
   bool create_if_not_exists = 5;
-  // catalog name and schema name is to accomplish storage path
-  // catalog name
-  string catalog = 6;
-  // schema name
-  string schema = 7;
+  // Region storage path
+  string path = 6;
   // Options of the created region.
-  map<string, string> options = 8;
+  map<string, string> options = 7;
   // TODO: add partition def
 }
 
@@ -101,13 +98,10 @@ message OpenRequest {
   uint64 region_id = 1;
   // Region engine name
   string engine = 2;
-  // catalog name and schema name is to accomplish storage path
-  // catalog name
-  string catalog = 3;
-  // schema name
-  string schema = 4;
+  // Region storage path
+  string path = 3;
   // Options of the opened region.
-  map<string, string> options = 5;
+  map<string, string> options = 4;
 }
 
 message CloseRequest { uint64 region_id = 1; }