Pyopal

Fixed
- Extra key in `pyproject.toml` causing build issues with version `0.11.0` of `scikit-build-core`.
- Broken detection of default SSE2 support for x86-64 CPUs on Windows.
- Missing `opal.h` file in Python site install to allow Cython imports.

Added
- Support for Python 3.13.

Changed
- Bump required `scoring-matrices` dependency to `v0.3.0`.
- Reorganize project to build with CMake and `scikit-build-core`.
- Update documentation to use the PyData theme.

Fixed
- Signature of Cython classes constructors not displaying in documentation.

Removed
- Support for Python 3.6.

Fixed
- Import of `pyopal` on non-AVX2-enabled CPUs causing a crash ([7](https://github.com/althonos/pyopal/issues/7)).
- Type hints for `Database.__init__` not accepting `alphabet` as a Python string.

Changed
- Use `scoring-matrices` package to handle scoring matrices.
- Import Cython classes from `pyopal.lib` in the main `pyopal` namespace.

Fixed
- Patching of architecture flags of MacOS compilers.

Removed
- The `ScoreMatrix` class from `pyopal.lib`.

Fixed
- Segmentation fault when attempting to align to an empty `Database` ([6](https://github.com/althonos/pyopal/issues/6)).

Fixed
- Broken behaviour of the `ordered` keyword in `pyopal.align`.