docs: Googlestyle docstrings and initial help sections

[vaeng]

I reworked all of the docstrings, the docs layout and structure and started with introduction texts, faq etc.

Also initial groundworks to test the examples and include them directly from the test files into the docs.

[Copilot]

Pull request overview

This PR modernizes and expands the documentation for the DeviceAccess Python bindings by converting many pybind11 docstrings to Google-style (Napoleon-compatible) docstrings, reorganizing the Sphinx docs into a more structured set of pages, and introducing an initial mechanism to source example snippets from executable test code.

Changes:

• Updated pybind11 docstrings across multiple bindings to Google-style sections (Args/Returns/See Also/Raises) and improved API reference generation via Sphinx autosummary + napoleon.
• Added new documentation pages (overview/getting started/user guide/examples/FAQ/troubleshooting) and refreshed the Sphinx configuration/theme.
• Added initial “doc examples” tests and accompanying dummy map/dmap files intended for inclusion into docs via literalinclude.

Reviewed changes

Copilot reviewed 26 out of 45 changed files in this pull request and generated 22 comments.

Show a summary per file

File	Description
tests/testDocExamples.py	Adds executable example snippets intended to be included in Sphinx docs.
tests/documentationExamples/someDummyModule.map	Dummy module map used by documentation examples/tests.
tests/documentationExamples/someCrate.dmap	Dummy dmap used by documentation examples/tests.
src/RegisterCatalogue.cc	Updates docstrings/args for RegisterCatalogue/RegisterInfo/DataDescriptor bindings.
src/PyVoidRegisterAccessor.cc	Enhances docstrings and adds argument annotations for VoidRegisterAccessor bindings.
src/PyVersionNumber.cc	Expands VersionNumber comparison/repr bindings and docstrings.
src/PyTwoDRegisterAccessor.cc	Updates docstrings and adds arg annotations for 2D accessor bindings.
src/PyTransferGroup.cc	Adds/expands TransferGroup docstrings and argument annotations.
src/PyScalarRegisterAccessor.cc	Updates scalar accessor docstrings to Google style with See Also/Returns.
src/PyReadAnyGroup.cc	Expands ReadAnyGroup/Notification docs and argument annotations.
src/PyOneDRegisterAccessor.cc	Updates 1D accessor docstrings and adds __getattr__ docs/arg name.
src/PyDevice.cc	Updates Device docstrings to Google style; reorganizes write() documentation.
src/PyDataType.cc	Updates DataType docstrings to Google style.
src/PyDataConsistencyGroup.cc	Improves DataConsistencyGroup docstrings and updates MatchingMode docs.
src/deviceaccessPython.cc	Updates module-level docs; adds argument names and richer docstrings for core types.
pyproject.toml	Adds a docs optional dependency group.
doc/*.rst	Introduces new top-level docs pages and rewrites the docs landing/index structure.
doc/generated/*.rst	Adds autosummary-generated API stubs for the reference section.
doc/conf.py.in	Updates Sphinx setup (autosummary, typehints, intersphinx, RTD theme, import mocking).

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