improvement: show backup button on supported db service stacks

app/Models/StandaloneMysql.php

@@ -295,4 +295,9 @@ class StandaloneMysql extends BaseModel
             return $parsedCollection->toArray();
         }
     }
+
+    public function isBackupSolutionAvailable()
+    {
+        return true;
+    }
 }