feat: add password auth flag

proto/api/v1/workspace_service.proto

@@ -23,6 +23,8 @@ message WorkspaceProfile {
   string mode = 3;
   // public is a flag that the instance is open for other users.
   bool public = 4;
+  // password_auth is a flag whether the instance allows password authentication.
+  bool password_auth = 5;
 }
 
 message GetWorkspaceProfileRequest {}