[client-python] chore(docs): fix readthedocs (#69)

[ncarenton]

Proposed changes

Fix the ReadTheDocs documentation build and restore working documentation links.

Context

The ReadTheDocs documentation was broken. A new RTD project (openaev-client-for-python) was created and configured to build the docs successfully.

Changes

• .readthedocs.yml: Clean up config, remove unnecessary comments and formats: all. Install the package itself (path: .) alongside doc requirements so autoapi can introspect the source.
• docs/conf.py: Migrate from deprecated autoapi.sphinx to autoapi.extension, configure autoapi_dirs and autoapi_options for proper API reference generation, remove boilerplate comments.
• docs/requirements.txt: Upgrade dependencies — autoapi
  2.0.1 → sphinx-autoapi 3.4.0, sphinx 8.2.3 → 9.1.0, sphinx_rtd_theme 3.0.2 → 3.1.0, add astroid 3.3.8.
• docs/index.rst: Remove reference to old pyoaev/pyoaev page that no longer exists (now auto-generated by autoapi).
• README.md: Update API reference link to the new autoapi URL.
• docs/_static/.gitkeep: Ensure _static directory exists for the build.

Working links

• 📖 Getting started: https://openaev-client-for-python.readthedocs.io/en/latest/client_usage/getting_started.html
• 📚 API reference: https://openaev-client-for-python.readthedocs.io/en/latest/autoapi/index.html

Checklist

• I consider the submitted work as finished
• I tested the code for its functionality
• I wrote test cases for the relevant uses case
• I added/update the relevant documentation
• Where necessary I refactored code to improve the overall quality
• For bug fix → I implemented a test that covers the bug

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.06%. Comparing base (58abf4c) to head (ae61bfb).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #215      +/-   ##
==========================================
- Coverage   70.41%   70.06%   -0.35%     
==========================================
  Files          58       49       -9     
  Lines        2329     1941     -388     
==========================================
- Hits         1640     1360     -280     
+ Misses        689      581     -108     

Flag	Coverage Δ
connectors	70.06% <ø> (-0.35%)	⬇️

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[guzmud]

LGTM