add createMany fields to fieldMetadataService to batch field creation (#9957)

## Context
Not exposed in the API yet, this new method allows us to reduce the time
to create multiple fields at once, mostly during seeding. This allows us
to batch transactions and avoid recomputing the cache everytime.

With this change, we recompute the cache 7 times instead of 35 during
seeding. We could do the same for objects.

packages/twenty-server/src/engine/seeder/seeder.service.ts

@@ -37,13 +37,13 @@ export class SeederService {
       throw new Error("Object metadata couldn't be created");
     }
 
-    for (const fieldMetadataSeed of objectMetadataSeed.fields) {
-      await this.fieldMetadataService.createOne({
+    await this.fieldMetadataService.createMany(
+      objectMetadataSeed.fields.map((fieldMetadataSeed) => ({
         ...fieldMetadataSeed,
         objectMetadataId: createdObjectMetadata.id,
         workspaceId,
-      });
-    }
+      })),
+    );
 
     const objectMetadataAfterFieldCreation =
       await this.objectMetadataService.findOneWithinWorkspace(workspaceId, {