docs: add theme hosting and URL configuration documentation

[Ang-m4]

Description

This pull request updates the plugins/tutor-contrib-paragon/README.rst file to document new functionality for hosting and managing compiled themes in the Paragon plugin for Tutor. The changes focus on enabling static hosting of themes, configuring theme URLs, and providing a flexible structure for theme management.

New Features for Theme Hosting and Configuration:

• Static Hosting for Compiled Themes: Added support for serving compiled themes directly via an Nginx service. This can be enabled by setting PARAGON_SERVE_COMPILED_THEMES = true. The service hosts themes from the path defined by PARAGON_COMPILED_THEMES_PATH and injects URLs into the LMS configuration under the PARAGON_THEME_URLS setting. Only minified CSS files (*.min.css) are served.

• Environment-Specific Theme URLs: Documented how URLs are adjusted based on the environment:

  • In local environments, URLs reference the LMS service and are redirected via Caddy.
  • In development environments, URLs point directly to the Paragon static service.

Theme Configuration Structure:

• PARAGON_THEME_URLS Setting: Detailed the structure of the PARAGON_THEME_URLS setting in the LMS MFE_CONFIG dictionary, which includes:
  • A core section for base styles.
  • A variants section for all the themes.

[Asespinel]

The documentation provided here is clear, structured, and highly informative. It explains not only how to enable the compiled theme hosting functionality via PARAGON_SERVE_COMPILED_THEMES, but also outlines how the system behaves across local and development environments, including precise URL examples. The breakdown of the PARAGON_THEME_URLS structure is especially helpful, covering core, defaults, and variant behavior in a way that's easy to understand and extend. This level of detail makes the setup approachable for new developers and ensures smooth integration with MFEs. Excellent job on providing practical, production-ready documentation.

[Ang-m4]

Closing this PR as the new documentation will be handled in: openedx#39