feat(core): Unify application components shutdown (#8097)

## Summary

Add `ShutdownService` and `OnShutdown` decorator for more unified way to
shutdown different components. Use this new way in the following
components:

- HTTP(S) server
- Pruning service
- Push connection
- License

---------

Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>

packages/cli/src/push/index.ts

@@ -14,6 +14,7 @@ import { WebSocketPush } from './websocket.push';
 import type { PushResponse, SSEPushRequest, WebSocketPushRequest } from './types';
 import type { IPushDataType } from '@/Interfaces';
 import type { User } from '@db/entities/User';
+import { OnShutdown } from '@/decorators/OnShutdown';
 
 const useWebSockets = config.getEnv('push.backend') === 'websocket';
 
@@ -70,6 +71,11 @@ export class Push extends EventEmitter {
 	sendToUsers<D>(type: IPushDataType, data: D, userIds: Array<User['id']>) {
 		this.backend.sendToUsers(type, data, userIds);
 	}
+
+	@OnShutdown()
+	onShutdown(): void {
+		this.backend.closeAllConnections();
+	}
 }
 
 export const setupPushServer = (restEndpoint: string, server: Server, app: Application) => {