[iso_build.sh] Review and added new features

* Add SABAYON_EXTRA_PKGS variable for add custom
    packages on building without review specs file
    (for development tests)

  * add option --only-dev

  * integrate installation of enman repositories.
    Currently this operation is done on sources chroot.
    To move as plugin of molecule.

  * add option for unmasking of packages through
    SABAYON_UNMASK_PKGS

  * Add option --skip-docker-rmi

scripts/inner_chroot_script.sh

@@ -114,6 +114,10 @@ sed -i "/^::1/ s/localhost/localhost sabayon/" /etc/hosts
 # setup postfix local mail aliases
 newaliases
 
+equo i sys-boot/plymouth x11-themes/sabayon-artwork-plymouth-default-17
+
+echo "PLYMOUTH THEME LIST:"
+plymouth-set-default-theme --list
 # Set Plymouth default theme, newer artwork has the sabayon theme
 is_ply_sabayon=$(plymouth-set-default-theme --list | grep sabayon)
 if [ -n "${is_ply_sabayon}" ]; then