Stateless Refactoring of Core Interpreter / Postprocessing Semantics / noscore rewrite mode

[lbeurerkellner]

This is a bit of a messy PR with a complete reimplementation of the PromptInterpreter, relying entirely on storing interpreter state in the decoder tree nodes. This fixes a few issues, that could occur with branching decoders and state tracking.

Other changes include:

• Improved @lmql.query support (no need to doubly-escape newlines anymore)
• noscore option for rewrite() for decoders that do not need the logprobs of deterministic prompt parts. This leads to a ~30% speedup for argmax/sample with the example queries in the playground.

I will do a PyPI release after merging these changes.