Implement BullMQ for background job processing

* new REDIS_URL environment variable

apps/server/src/integrations/queue/constants/queue.constants.ts

@@ -0,0 +1,7 @@
+export enum QueueName {
+  EMAIL_QUEUE = '{email-queue}',
+}
+
+export enum QueueJob {
+  SEND_EMAIL = 'send-email',
+}