Deprecate `-keyboard_layout` cmdline_param

'-keyboard_layout' Allowed at some point users to switch between the German qwertz and American azerty layouts which doesn't appear to be the case anymore.

This task will thus do the following:
* Deprecate, or remove the '-keyboard_layout' command
* Use SDL methods to automatically detect regional keyboard layouts from the OS setting for text input boxes. (Controls should still use scan codes instead of key codes)
* Automatically translate scan code into key codes in all places that controls bindings are printed to screen (training messages, controls config menus)

Additionally:
* Preset files and CCFG override files will treat the keyboard bindings as scancodes, unless an optional 'keyboard_layout' element is present to designate the layout.