Move common live functionality to a new layer

os/layers/contestant/hooks/live/2010-contestant.hook.chroot

@@ -21,9 +21,6 @@ $DISABLE_DESKTOP /usr/share/applications/gnome-bluetooth-panel.desktop
 $DISABLE_DESKTOP /usr/share/applications/gnome-online-accounts-panel.desktop
 $DISABLE_DESKTOP /usr/share/applications/gnome-sharing-panel.desktop
 
-# Enable the live system configuration script at boot.
-systemctl enable live-config.service
-
 # Disable kexec-tools services.
 # We want to load kexec manually, and execution of kexec is already done by systemd.
 systemctl disable kexec-load.service

os/layers/contestant/includes.chroot/etc/dconf/db/local.d/00-disable-screensaver-lock

@@ -1,3 +0,0 @@
-# Disable lock on blank screen
-[org/gnome/desktop/screensaver]
-lock-enabled = false

os/layers/contestant/includes.chroot/etc/dconf/db/local.d/00-disallow-updates

@@ -1,5 +0,0 @@
-# Disable "Updates available" notifications and auto updates.
-# Updates which require reboot are useless on live systems,
-# and other updates would be installed on each boot.
-[org/gnome/software]
-allow-updates = false

os/layers/contestant/includes.chroot/etc/systemd/system/live-config.service

@@ -1,14 +0,0 @@
-[Unit]
-Description=custom configuration of live system during boot.
-Before=basic.target
-After=local-fs.target systemd-tmpfiles-setup.service
-DefaultDependencies=no
-ConditionKernelCommandLine=boot=live
-
-[Service]
-Type=oneshot
-RemainAfterExit=yes
-ExecStart=/usr/local/bin/live-config
-
-[Install]
-WantedBy=basic.target