feat: implement drop flow procedure (#3877)

* feat: implement `destroy_flow_metadata` method

* chore: bump proto to 65c1364

* feat: implement the drop flow procedure

* feat: add `MockFlownodeManager`

* tests: add tests for create flow & drop flow procedure

* chore: apply suggestions from CR

* chore: use `ClusterId`

src/common/error/src/status_code.rs

@@ -97,6 +97,11 @@ pub enum StatusCode {
     /// User is not authorized to perform the operation
     PermissionDenied = 7006,
     // ====== End of auth related status code =====
+
+    // ====== Begin of flow related status code =====
+    FlowAlreadyExists = 8000,
+    FlowNotFound = 8001,
+    // ====== End of flow related status code =====
 }
 
 impl StatusCode {
@@ -125,8 +130,10 @@ impl StatusCode {
             | StatusCode::EngineExecuteQuery
             | StatusCode::TableAlreadyExists
             | StatusCode::TableNotFound
-            | StatusCode::RegionNotFound
             | StatusCode::RegionAlreadyExists
+            | StatusCode::RegionNotFound
+            | StatusCode::FlowAlreadyExists
+            | StatusCode::FlowNotFound
             | StatusCode::RegionReadonly
             | StatusCode::TableColumnNotFound
             | StatusCode::TableColumnExists
@@ -161,10 +168,12 @@ impl StatusCode {
             | StatusCode::InvalidSyntax
             | StatusCode::TableAlreadyExists
             | StatusCode::TableNotFound
+            | StatusCode::RegionAlreadyExists
             | StatusCode::RegionNotFound
+            | StatusCode::FlowAlreadyExists
+            | StatusCode::FlowNotFound
             | StatusCode::RegionNotReady
             | StatusCode::RegionBusy
-            | StatusCode::RegionAlreadyExists
             | StatusCode::RegionReadonly
             | StatusCode::TableColumnNotFound
             | StatusCode::TableColumnExists