Fix and improve Control content

[AnesBenmerzoug]

This PR addresses some of the feedback we received and issues we encountered during the first iteration of the Control Training. This is related to issue #10

Changes

• Add diagrams/concept maps to help participants navigate the field of Control Theory.
• Remove slycot from the dependencies.
• Add diagram explaining different approaches to solve the Optimal Control Problem.
• Reorganize dependencies in pyproject.toml
• Use multi-stage build in Dockerfile (This reduces the final image size to ~7GB and the largest layer being 5.47GB)
• Add poetry.lock to dockerignore file.
• Update readme instructions.
• Skip rendering when running control notebooks inside a container.