Reduce usages of reflection language

Currently, there are 43 usages of `de.slisson.mps.reflection` that can't be removed + 23 direct calls to the ReflectionUtil methods. A few of them are for [jgraphx](https://github.com/jgraph/jgraphx) and are needed for the diagram language which we can't change, the others are for MPS itself. The language itself was already deprecated years ago. The calls with this language are [expensive](https://docs.oracle.com/javase/tutorial/reflect/index.html#:~:text=drawbacks%20of%20reflection) and should be avoided.

The fields and methods might become public in the future, but currently this ticket is just a reminder, as there is nothing that can be done here at the moment.

Start by inventorying the reported usages of de.slisson.mps.reflection and the direct ReflectionUtil calls. The issue states that the relevant MPS fields and methods are not currently public, so there is no actionable entry point or completion criterion until that changes.

Written by the indexing model from the issue text.