Metadata: specify DSS-Python and OpenDSSDirect.py versions for the beta

v0.2.4: use backend v0.14.5, implement "contains" for buses, updated …

…changelog.

pyproject.toml: Use the backend as the anchor package, let DSS-Python…

… float.

Batch: refactored to allow new filters; new tests, docs. Updated depe…

…ndencies.

RegisterValues: Remove the previous workaround, which is causing issu…

…es now.

PDElement: pctNormal and pctEmergency; upgrade versions.

Update changelog

Update changelog

pyproject.toml: depend on dss_python_backend for a fixed version

Merge local changes:

- Use `pyproject.toml`
- Generate code based on the latest schema, notably `DynOut` is now a list of strings instead of a single string
- SetterFlags implemented
- Tests updated
- Type hints adjusted for a better dev experience. Still needs more work.
- Migrate (copy and adapt) some more code from DSS-Python
- Handle integration with DSS-Python and OpenDSSDirect.py
- Fix some Bus functions (renamed in DSS C-API)
- Initial documentation