Kubernetes Deployment Manifest

**Context**: 
Kubernetes is an open-source container orchestration system for automating the deployment, scaling, and management of containerized applications. A deployment manifest is a YAML or JSON file that defines the desired state of a Kubernetes deployment, including the container images, ports, environment variables, and other settings. The goal is to create a comprehensive deployment manifest that ensures reliable, scalable, and maintainable deployment of a containerized application.

**Detailed Instructions**: 
Create a Kubernetes deployment manifest for a web application that consists of a frontend and a backend service. The frontend is built using Node.js and exposed on port 3000, while the backend is built using Python and exposed on port 5000. The application requires a PostgreSQL database for data storage. The manifest should include the following specifications:
- Use the latest available version of the Node.js and Python images from Docker Hub.
- Set environment variables for the database connection, including `DB_HOST`, `DB_PORT`, `DB_USERNAME`, and `DB_PASSWORD`.
- Configure the deployment to use a Persistent Volume Claim (PVC) for data persistence.
- Define a service for the frontend and backend, with the correct port mappings and target ports.
- Implement liveness and readiness probes to ensure the application is healthy and responsive.
- Specify resource requests and limits for the containers to ensure efficient resource utilization.
- Use a ConfigMap to store configuration data for the application.

**Output Format**: 
The output should be a valid YAML file that can be applied to a Kubernetes cluster using the `kubectl apply` command. The manifest should include the following sections:
- `apiVersion` and `kind` to specify the Kubernetes API version and the type of resource being defined.
- `metadata` to provide metadata about the deployment, such as the name and namespace.
- `spec` to define the specification of the deployment, including the containers, services, and other settings.

**Examples**: 
For reference, the following is an example of a simple deployment manifest:
```yml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: example-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: example
  template:
    metadata:
      labels:
        app: example
    spec:
      containers:
      - name: example-container
        image: example/image
        ports:
        - containerPort: 80
```
However, the output should be a more comprehensive manifest that includes all the specifications outlined in the detailed instructions.