get rid of vesamenu/livemode

from now on create_livestick.* will create pure installer
sticks. (TODO: cosmetics. rename to create_installstick)

- syslinux/vesamenu is pain with some boards. syslinux 4.x is even more pain
- now we provide images which have the shiny menu/live thingie. make image.
- initramfs/init: FILE=xxx is not needed anymore. images have two ext4 partitions

side note: be very careful when adding features to installer / installer scripts,