Added new pages for Sphinx exercise and Sphinx proof extensions, including installation and usage instructions. Updated references, credits, and feature pages to reflect inclusion in TeachBooks Template and Favourites. Improved consistency of external links and badges, and updated submodules to latest versions.
Split the TeachBooks Python Package and Deploy Book Workflow documentation into dedicated intro pages (teachbooks_intro.md, DBW_intro.md), update references and links throughout feature pages, and revise the _toc.yml structure to include new sections. Added clarifications to favourites and live_code features, improving organization and navigation for users.
