Bump ansible-core and Python versions

[felixfontein]

Ref: https://github.com/ansible-collections/news-for-maintainers/issues/48

• Use Python 3.11 for build action testing.
• Use ansible-core 2.15 on Python 3.11 for Wiki.
• Bump defaults for shared workflows to stable-2.15 and Python 3.10.

[felixfontein]

Start CI.

[felixfontein]

@briantist thanks for reviewing!