Easier setup for keyboard layout selector
As a Desktop User, I would like to configure the keyboard layout in an easier manner.
- AC1 The installation of the OS provide the option of adding all the keyboard layouts I need, i.e. more than one.
- AC2 On an installed OS, I can set up the keyboard layouts from only one control panel for both 'desktop session' and 'login screen', i.e. not having a separated control panel for each one.
- Improve the tool "region & language" to set up both 'desktop session' and 'login screen' with the same controls. (No more having to use a different panel to configure the login screen)
- Improve the installer to be able to install the system with the desired keyboard layout, so you don't have to configure them later after installation.