Handle relations separately for remotes (twentyhq#5538)

Remote object id columns are not removed anymore when a remote object is
unsynced.
This is because we do not use relations anymore. We only created the id
field. So the current behavior that was implemented for custom objects,
to retrieve the fields to deleted, does not work.

Since remote object relations are really different, I extracted the
logic from `objectMetadataService`. It now handles only the relations
for custom objects creation and deletion (this part should be extracted
as well).

I create a new remote table relation service that will:
- fetch objects metadata linked to remotes (favorites,
activityTargets...)
- look for columns based on remote object name
- delete the fields and columns

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

@@ -20,6 +20,7 @@ import { FeatureFlagModule } from 'src/engine/core-modules/feature-flag/feature-
 import { FeatureFlagEntity } from 'src/engine/core-modules/feature-flag/feature-flag.entity';
 import { WorkspaceCacheVersionModule } from 'src/engine/metadata-modules/workspace-cache-version/workspace-cache-version.module';
 import { BeforeUpdateOneObject } from 'src/engine/metadata-modules/object-metadata/hooks/before-update-one-object.hook';
+import { RemoteTableRelationsModule } from 'src/engine/metadata-modules/remote-server/remote-table/remote-table-relations/remote-table-relations.module';
 
 import { ObjectMetadataService } from './object-metadata.service';
 import { ObjectMetadataEntity } from './object-metadata.entity';
@@ -43,6 +44,7 @@ import { ObjectMetadataDTO } from './dtos/object-metadata.dto';
         WorkspaceMigrationRunnerModule,
         WorkspaceCacheVersionModule,
         FeatureFlagModule,
+        RemoteTableRelationsModule,
       ],
       services: [ObjectMetadataService],
       resolvers: [