Creating submodel services can be quite cumbersome, as it requires building a Spring Boot application and creating a Docker script each time.

It would be beneficial to have a pre-configured Docker image that can be customized or extended. I propose developing an approach where Java classes can be mapped to an operation. A method of the Java object would then be called upon an HTTP-POST to the operation's invoke URL.

The Java classes do not need to be built against the basys-server-sdk and can be provided either as source code (which will be compiled within the service) or as .class or .jar files.

This approach would allow for quick testing and setup of submodel services. Additionally, deploying a custom service through the Docker registry would be straightforward by using the created image as a base image and copying the necessary classes and configurations into the image.

The pull request initially includes only an in-memory variant, which can then be extended with MongoDB persistence, authorization and a registry-integration-feature.