Re-structure to use C++20 modules

[hugsy]

• https://www.kitware.com/import-cmake-c20-modules/
• https://www.kitware.com/import-cmake-the-experiment-is-over/
• https://www.kitware.com/cmake-3-28-0-available-for-download/ << Required
• https://youtu.be/5X803cXe02Y
• https://youtu.be/_x9K9_q2ZXE