feat: add ConIFactory to support oidc and m2m workflows

[totonga]

This pull request introduces support for OIDC authentication, adds a new ConIFactory class, and improves documentation and dependency management. It also updates the public API to expose ConIFactory and makes minor improvements to the README and docstrings. The most important changes are summarized below:

OIDC Authentication Support & Dependency Management:

• Added an optional oidc dependency group with pip-system-certs and requests-oauthlib for OIDC authentication in pyproject.toml and documented them in both CONTRIBUTING.md and the VSCode spellchecker settings. [1] [2] [3] [4]

Public API and Import Improvements:

• Exposed the new ConIFactory class in the odsbox package's public API, including lazy loading and improved error messages for missing OIDC dependencies. Updated __all__, __getattr__, and __dir__ accordingly. [1] [2] [3]
• Updated imports in documentation and tests to use from odsbox import ConI for consistency. [1] [2]

Documentation Enhancements:

• Added documentation for the new con_i_factory module in both the Sphinx docs (docs/index.rst, docs/odsbox.rst) and improved the example output in the README. [1] [2] [3]

Code Quality and Maintenance:

• Bumped versions of some test dependencies for better compatibility and maintenance.
• Updated the version number to 1.2.0 in __init__.py.

Docstring and Usability Improvements:

• Expanded the docstring and constructor documentation for the Transaction class, providing a clear usage example. [1] [2]