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/utils/build-migrations-for-custom-object-relations.util.ts

@@ -208,31 +208,4 @@ export const buildMigrationsForCustomObjectRelations = (
       },
     ],
   },
-  {
-    name: computeObjectTargetTable(createdObjectMetadata),
-    action: WorkspaceMigrationTableActionType.ALTER,
-    columns: [
-      {
-        action: WorkspaceMigrationColumnActionType.CREATE,
-        columnName: 'position',
-        columnType: 'float',
-        isNullable: true,
-        defaultValue: null,
-      } satisfies WorkspaceMigrationColumnCreate,
-    ],
-  } satisfies WorkspaceMigrationTableAction,
-  // This is temporary until we implement mainIdentifier
-  {
-    name: computeObjectTargetTable(createdObjectMetadata),
-    action: WorkspaceMigrationTableActionType.ALTER,
-    columns: [
-      {
-        action: WorkspaceMigrationColumnActionType.CREATE,
-        columnName: 'name',
-        columnType: 'text',
-        defaultValue: "'Untitled'",
-        isNullable: false,
-      } satisfies WorkspaceMigrationColumnCreate,
-    ],
-  } satisfies WorkspaceMigrationTableAction,
 ];