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/core/utils/seed-feature-flags.util.ts

@@ -81,6 +81,11 @@ export const seedFeatureFlags = async ({
         workspaceId: workspaceId,
         value: true,
       },
+      {
+        key: FeatureFlagKey.IS_FILES_FIELD_ENABLED,
+        workspaceId: workspaceId,
+        value: true,
+      },
     ])
     .execute();
 };

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>,
 ];

packages/twenty-server/src/engine/workspace-manager/workspace-migration/workspace-migration-runner/utils/field-metadata-type-to-column-type.util.ts

@@ -35,6 +35,7 @@ export const fieldMetadataTypeToColumnType = <Type extends FieldMetadataType>(
     case FieldMetadataType.SELECT:
     case FieldMetadataType.MULTI_SELECT:
       return 'enum';
+    case FieldMetadataType.FILES:
     case FieldMetadataType.RAW_JSON:
       return 'jsonb';
     case FieldMetadataType.TS_VECTOR: