Decaylanguage

* Parsing of decay files (aka .dec files):
- Added support for many new EvtGen models and keywords (mostly for LHCb).
- Added first implementation of decay descriptors, decay chains represented as strings.
- Added support for empty or minimalistic decay files.
* Universal representation of decay chains:
- Several enhancements,e.g. for handling of decay descriptors.
- Improvements to type hints.
* CI and tests:
- Updates to pre-commit hooks and CI YAML files.

* CI and tests:
- Updates to pre-commit hooks and CI YAML files.

* Universal representation of decay chains:
- Better test coverage for dec and decay submodules.
* Modeling for GooFit/AmpGen:
- Major update to AmpGen2GooFit parsing.
* Miscellaneous:
- Moved over to using Ruff.
* CI and tests:
- Updates to pre-commit hooks and CI YAML files.

* Universal representation of decay chains:
- Test suite extended for a significantly better test coverage.
* CI and tests:
- Run doctests via pytest.
- Updates to pre-commit hooks and CI YAML files.

* Dependencies:
- Package dependent on `Particle` version 0.21.x.
- Adapted to Python 3 only `Lark` 1.x series.
- Support for Python 3.11 added and support for Python 3.6 removed.
* Parsing of decay files (aka .dec files):
- Updated to the latest Belle II master file DECAY.DEC.
- Added support for ModelAlias keyword used in Belle II decay files.
* Miscellaneous:
- Added a CITATION.cff file.
- Moved over to using hatchling.
- Started using AllContributors to acknowledge contributions explicitly.
* CI and tests:
- Updates to pre-commit hooks and CI YAML files.
- Various improvements to the CI.

* Parsing of decay files (aka .dec files):
- Minor improvements such as in type checking.
- Documentation updates.
- More tests.
* CI and tests:
- Several improvements to GHAs.
- Various hooks version updates.
- Added a `dependabot.yml`.