Files v2 - Add new FILES field type (#17236)

In this PR : 
- New field type FieldMetadataType.FILES added (as jsonb in DB)
- Backend: GraphQL types, validation, REST API schema, data processor
handling
- Frontend: field configuration in settings
- Feature flag IS_FILES_FIELD_ENABLED to gate the feature
- Integration tests for create/filter validation
- Dev seed: Feature flag enabled + FILES field on survey result object


To do in next PRs : 
- Backend : 
-- new workspaceFile controller (for download) & new workspaceFile
upload resolver (for upload)
-- pre-hook/post-hook to ensure fileId existence + listener to ensure
cleaning
- Frontend : FILES field display/edit in table view, record, ...

packages/twenty-server/src/engine/workspace-manager/dev-seeder/metadata/custom-fields/constants/survey-results-field-seeds.constant.ts

@@ -58,4 +58,13 @@ export const SURVEY_RESULT_CUSTOM_FIELD_SEEDS: FieldMetadataSeed[] = [
       displayedMaxRows: 1,
     },
   } as FieldMetadataDTO<FieldMetadataType.TEXT>,
+  {
+    type: FieldMetadataType.FILES,
+    label: 'Files',
+    name: 'files',
+    icon: 'IconFiles',
+    settings: {
+      maxNumberOfValues: 5,
+    },
+  } as FieldMetadataDTO<FieldMetadataType.FILES>,
 ];