- Updates Doxyfile for Doxygen 1.18.0 and minifies Doxyfile
- Use PROJECT_LOGO & PROJECT_ICON in Doxyfile
- Add custom Doxygen CSS
- Move documentation comments in first-party code from source files to
their corresponding headers, where applicable
- Resolves nearly all Doxygen warnings in first-party code
- Remove unused INPUTDIRS from doc/CMakeLists.txt
- Use CMake's DOXYGEN_ADD_DOCS() instead of a custom doc target
- Bump portsmf submodule to get upstream Doxygen fixes
- Only autorun Doxygen CI for master branch
- Skip Doxygen CI if Github Pages aren't enabled