Migrate metadata cache (#16030)

## Context
Deprecating legacy ObjectMetadata from cache in favor of flat entities.
Introducing utils to build byName/byNameSingular/byNamePlural in
isolated cases

## Next
- I had to introduce a util to build from flat to legacy
objectMetadataMaps, we should instead use flat maps directly when needed
(datasource, schema generation, etc)
- Deprecate metadata version in the cache
- Use the new cache strategy for flat entities with permissions and
feature flags and inject in the global datasource context

packages/twenty-server/src/engine/dataloaders/dataloader.interface.ts

@@ -12,7 +12,7 @@ import { type FieldMetadataDTO } from 'src/engine/metadata-modules/field-metadat
 import { type RelationDTO } from 'src/engine/metadata-modules/field-metadata/dtos/relation.dto';
 import { type IndexFieldMetadataDTO } from 'src/engine/metadata-modules/index-metadata/dtos/index-field-metadata.dto';
 import { type IndexMetadataDTO } from 'src/engine/metadata-modules/index-metadata/dtos/index-metadata.dto';
-import { type ObjectMetadataItemWithFieldMaps } from 'src/engine/metadata-modules/types/object-metadata-item-with-field-maps';
+import { type ObjectMetadataDTO } from 'src/engine/metadata-modules/object-metadata/dtos/object-metadata.dto';
 
 export interface IDataloaders {
   relationLoader: DataLoader<RelationLoaderPayload, RelationDTO | null>;
@@ -39,6 +39,6 @@ export interface IDataloaders {
 
   objectMetadataLoader: DataLoader<
     ObjectMetadataLoaderPayload,
-    ObjectMetadataItemWithFieldMaps | null
+    ObjectMetadataDTO | null
   >;
 }