Container Base Generator: Support generation of multi-deployments

[frademacher]

Currently, the Container Base Generator for Docker and Kubernetes only supports the deployment of one microservice per container. While this approach is common practice, the Operation Modeling Language still supports the definition of multi-deployments (more than one service per container).

However, the Container Base Generator prevents the generation of multi-deployments by means of intermediate model validation. To align the generator with the modeling language, an investigation should be conducted to what extent it is feasible to support multi-deployment with the generator.

In the ideal case, the Container Base Generator should support the generation of multi-deployments for both Docker and Kubernetes, and only yield a warning in the event of a detected multi-deployment (something along the lines "Detected multi-deployment on container X, will proceed in generation. Please consider refactoring towards single-deployment in the future for increased scalability.").