Add XML importing + exporting!

[Flohhhhh]

This was one of my favorite features in CS1, I love to spend lots of time on interchanges and re-use them.

Would be cool if we could paste xml from outside the game as well, or at least create files that would be loaded in game

[Quboid]

This will be added but it will take a lot of time as it depends on other features, in particular copying.

[Flohhhhh]

Of course, glad to know it's in the roadmap, I'll consider learning some Unity to help out at some point 🫡