[RFR] Introduce component inheritance

```yaml
applications:
    producer:
        type: python
        volumes:
            .: /app
        after_script: python /app/app.py
        custom:
            pip_modules: [pika==0.9.8]
            
    worker1:
        after_script: python /app/worker.py
        extends: producer
        
    worker2:
        after_script: python /app/worker.py
        extends: producer
``` 

- [x] Allows component inheritance
- [x] Add tests on component inheritance
- [x] Add a `rabbitMQ` template
- [x] Add a `python`/`RabbitMQ` example with component inheritance