Creates a layer outside the game config layer system and passes it to the created gfx widows, so as to not interfere with the global config system. Supports multiple game properties being open at once. Supports editing while a game is playing, but the options only save and update the active game when the window is closed. Right-clicking will remove a property from the game ini.
This reduces code duplication in the different ConfigControls. This is helpful for the next commit, which will modify the now deduplicated code.