Add element type information and ids to the testing API

[tronical]

trafficstars

This requires additional debug information to be generated, which is disabled by default in Rust and in C++ for release builds.

[tronical]

Oops, too early to review. There are some issues.

[tronical]

I need to rebase this as the CI merges this with master and then it doesn't compile anymore due to compiler API changes.

[tronical]

Marking as draft until I've got all the things sorted out Olivier and I discussed. Some CI work left in particular. Will re-enable once it's ready for final review.