Anaconda/Features/Plymouthize

Installer images should use plymouth for boot progress. Everyone loves bootsplash, right?

Stuff that needs doin'

 * Fix up this feature page
 * : put plymouth in the initramfs
 * : customize boot splash to show progress for long-running items
 * fetching/mounting root/repo
 * fetching kickstart
 * etc.
 * : properly shut down plymouth for a smooth transition
 * see this  patch