Umaudemc

* The probabilistic model checker supports the `sample` operator with discrete distributions (Bernoulli and uniform with integer bounds).
* Minor bug fixes and code cleanup.
* Removed backward compatibility code for Python 3.8 (whose support ended in October 2024).

* Fixed a bug that causes an internal error when the observation of a QuaTEx expression is a constant.
* Fixed a bug in the parallel statistical simulator that affects macOS and Windows due to a different default behavior of the [`multiprocessing`](https://docs.python.org/3/library/multiprocessing.html#contexts-and-start-methods) package.

* The model checker for the Kleene-star semantics of the iteration (`--kleene-iteration` flag) now uses the more efficient builtin implementation of the strategy language introduced for the `pcheck` command when using Spot as backend. Opaque strategies are not supported yet, and the previous implementation is still used for other backends.
* New option `--kleene-iteration` to the `graph` command. It prints the graph used in the Kleene-aware model checker, where edges starting or terminating an iteration are annotated with an opaque identifier of the iteration.
* Fixed a bug in the `graph` command when printing probabilistic strategy-controlled graphs.
* The number of rewrites printed by `pcheck` with the `strategy` assignment method is more accurate.
* The web-based interface does no longer depend on the deprecated `cgi` module.
* The unmaintained GTK-based interface has been replaced by a thin wrapper around the web-based interface. Its only advantage is that a more confortable native file chooser is used for selecting Maude files. It requires GTK 4 and WebKitGTK 6.
* Removed backward compatibility code for very old versions of the `maude` Python library.

* Fixed a bug in the translation from QuaTEx to Python.
* Fixed a bug in the web interface when the result of a query is infinity.
* Test specifications in TOML are also admitted for Python ≥ 3.11.
* Switching to PEP 621 build system (pyproject.toml).

<details>
<summary><b>Changes in previous versions</b></summary>

* In `scheck`, the `strategy` assignment method has been renamed to `strategy-fast` and `strategy-full` has been renamed to `strategy`. Warnings are now printed by `strategy-fast` when local unquantified nondeterminism or conditional expressions are detected. However, conditional expressions whose conditions only contain tests can now safely used.

* The connection with the probabilistic model checker Storm now uses its Python bindings [StormPy](https://moves-rwth.github.io/stormpy/) if available. Otherwise, it falls back to the previous command-line communication.
* Weight annotations for `metadata` assignment method can now be terms depending on the matching substitution also in strategy-controlled models.
* The `graph` command can now show transition labels for models whose probabilities/rates have been assigned with the `strategy` method (it was the only case were edge labels were not printed).
* New method `MaudeModel.scheck` in the Python API for statistical model checking.
* Bug fixes related to the normalization of probabilities under the `strategy` method.