Add exceptions for metadata modules (#6070)

Class exception for each metadata module + handler to map on graphql
error

TODO left :
- find a way to call handler on auto-resolvers nestjs query (probably
interceptors)
- discuss what should be done for pre-hooks errors
- discuss what should be done for Unauthorized exception

packages/twenty-server/src/engine/metadata-modules/object-metadata/object-metadata.exception.ts

@@ -0,0 +1,15 @@
+import { CustomException } from 'src/utils/custom-exception';
+
+export class ObjectMetadataException extends CustomException {
+  code: ObjectMetadataExceptionCode;
+  constructor(message: string, code: ObjectMetadataExceptionCode) {
+    super(message, code);
+  }
+}
+
+export enum ObjectMetadataExceptionCode {
+  OBJECT_METADATA_NOT_FOUND = 'OBJECT_METADATA_NOT_FOUND',
+  INVALID_OBJECT_INPUT = 'INVALID_OBJECT_INPUT',
+  OBJECT_MUTATION_NOT_ALLOWED = 'OBJECT_MUTATION_NOT_ALLOWED',
+  OBJECT_ALREADY_EXISTS = 'OBJECT_ALREADY_EXISTS',
+}