Refactor tenant ORM integration (#1650)

* Refactor tenant ORM integration

* fix tests

server/src/tenant/metadata/object-metadata/object-metadata.service.ts

@@ -0,0 +1,21 @@
+import { Injectable } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+
+import { Repository } from 'typeorm';
+
+import { ObjectMetadata } from './object-metadata.entity';
+
+@Injectable()
+export class ObjectMetadataService {
+  constructor(
+    @InjectRepository(ObjectMetadata, 'metadata')
+    private readonly fieldMetadataRepository: Repository<ObjectMetadata>,
+  ) {}
+
+  public async getObjectMetadataFromDataSourceId(dataSourceId: string) {
+    return this.fieldMetadataRepository.find({
+      where: { dataSourceId },
+      relations: ['fields'],
+    });
+  }
+}