Implement BullMQ for background job processing

* new REDIS_URL environment variable

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

@@ -0,0 +1 @@
+export * from './queue.constants';

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',
+}

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

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+import { Global, Module } from '@nestjs/common';
+import { BullModule } from '@nestjs/bullmq';
+import { EnvironmentService } from '../environment/environment.service';
+import { parseRedisUrl } from '../../helpers';
+import { QueueName } from './constants';
+
+@Global()
+@Module({
+  imports: [
+    BullModule.forRootAsync({
+      useFactory: (environmentService: EnvironmentService) => {
+        const redisConfig = parseRedisUrl(environmentService.getRedisUrl());
+        return {
+          connection: {
+            host: redisConfig.host,
+            port: redisConfig.port,
+            password: redisConfig.password,
+          },
+          defaultJobOptions: {
+            attempts: 3,
+            backoff: {
+              type: 'exponential',
+              delay: 10000,
+            },
+          },
+        };
+      },
+      inject: [EnvironmentService],
+    }),
+    BullModule.registerQueue({
+      name: QueueName.EMAIL_QUEUE,
+    }),
+  ],
+  exports: [BullModule],
+})
+export class QueueModule {}