Add createdBy field on custom object creation (#6529)

In this PR, I'm:
- adding createdBy field (type ACTOR) on custom objects when created
- moving `name` and `position` default column to the set of columns
automatically creation on object creation
- fixing a bug on mutations (update / create), if the targetted object
has a 'data' custom field, it was conflicting with the payload ==> I
feel we need to refactor this part of the code but we can keep this for
a bit later as we plan to move out of pg_graphql

<img width="1198" alt="image"
src="https://github.com/user-attachments/assets/891c4a97-bab1-415c-8551-dabd5996a794">

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

@@ -265,6 +265,20 @@ export class ObjectMetadataService extends TypeOrmQueryService<ObjectMetadataEnt
               workspaceId: objectMetadataInput.workspaceId,
               defaultValue: 'now',
             },
+            {
+              standardId: CUSTOM_OBJECT_STANDARD_FIELD_IDS.createdBy,
+              type: FieldMetadataType.ACTOR,
+              name: 'createdBy',
+              label: 'Created By',
+              icon: 'IconCreativeCommonsSa',
+              description: 'The creator of the record',
+              isNullable: false,
+              isActive: true,
+              isCustom: false,
+              isSystem: false,
+              workspaceId: objectMetadataInput.workspaceId,
+              defaultValue: { name: "''", source: "'MANUAL'" },
+            },
             {
               standardId: CUSTOM_OBJECT_STANDARD_FIELD_IDS.position,
               type: FieldMetadataType.POSITION,