WIP: Implementation of SDIRK22

[SKopecz]

This is meant to fix #2875. The implementation is based on TRBDF2.

Checklist

• Appropriate tests were added
• Any code changes were done in a way that does not break public API
• All documentation related to code changes were updated
• The new code follows the
  contributor guidelines, in particular the SciML Style Guide and
  COLPRAC.
• Any new documentation only uses public API

Additional context

Add any other context about the problem here.

[oscardssmith]

I think it might make sense to wait on this until we have #2779 merged.

[SKopecz]

That will definitely simplify things.

[ChrisRackauckas]

I wonder if we should wait on that, since it should be done fairly soon.

But yes, thank you for finding this. I think this got messed up in the transition to the sublibrary.