* Allow to choose the style of the GDevelop logo (light, dark, colored or plain)
* Allow to choose the background color and an optional background image
* Allow to choose the size of the progress bar (with a minimum and maximum size)
* Allow to choose the duration of the fade in animations and the minimum time the loading screen is shown
* Use the **new preview button in the game properties** dialog to run a preview with the loading screen shown
* Update all CMakeLists of extensions to use clang-format
* Run clang-format on all Extensions
* Update GDCore CMakeLists.txt to add clang-format
* Run clang-format on GDCore files
* Update GDJS and GDCpp CMakeLists.txt to add clang-format
* Run clang-format on GDCpp and GDJS files