live exam ISO build process is now better structured

live_exam_os/Dockerfile

live_exam_os/config/00-bootloader/grub_config.cfg

live_exam_os/config/01-build_hooks/keyboard/keyboard

live_exam_os/config/01-build_hooks/nexus-exam.desktop

live_exam_os/config/01-build_hooks/ntp/timesyncd.conf

live_exam_os/config/01-build_hooks/packages.list.chroot

..._os/config/01-build_hooks/systemd/screen_settings.service

..._exam_os/config/01-build_hooks/systemd/screen_settings.sh

...s/config/01-build_hooks/themes/i3/xfwm4/bottom-active.png

...s/config/01-build_hooks/themes/i3/xfwm4/bottom-active.xpm

...config/01-build_hooks/themes/i3/xfwm4/bottom-inactive.png

...config/01-build_hooks/themes/i3/xfwm4/bottom-inactive.xpm

...fig/01-build_hooks/themes/i3/xfwm4/bottom-left-active.png

...fig/01-build_hooks/themes/i3/xfwm4/bottom-left-active.xpm

...g/01-build_hooks/themes/i3/xfwm4/bottom-left-inactive.png

...g/01-build_hooks/themes/i3/xfwm4/bottom-left-inactive.xpm

...ig/01-build_hooks/themes/i3/xfwm4/bottom-right-active.png

...ig/01-build_hooks/themes/i3/xfwm4/bottom-right-active.xpm

.../01-build_hooks/themes/i3/xfwm4/bottom-right-inactive.png

.../01-build_hooks/themes/i3/xfwm4/bottom-right-inactive.xpm