Add building and container recipes

[feegeer]

I was not sure how

From your pull request, it should be possible to create an executable container. After running the container, it should be possible to cd into cmake-exercise and then run the build_and_run.sh script.

was meant. I assumed it means that

• there should be a Dockerfile that can be built
• when running and interactively entering the container, there is a directory cmake-exercise, where build_and_run.sh can be run