Add Documentation Site

[threeal]

• Implemented the add_xml_docs CMake function to facilitate the generation of XML API documentation from the project's source code.
• Initialized the Sphinx project to enable the generation of comprehensive documentation.
  • Integrated Breathe to map the project's API to Sphinx.
• Added a configuration for Read the Docs, allowing the hosting of the project's documentation on that platform.
• Closes Documentation Site Integration #12.