This one is quite different already and utility-based name
was pretty clumsy; meet the new feature and retire the old
experimental one.

Please note that quite aggressive cleanups are implemented
within this stage2-based subprofile for the simple reason
that it has a single task to do; nothing else is expected
to be configured into it for that matter.

This functionality asks to be further moved into initrd of course;
adding it there will take a few more decisions to be made, mostly
regarding user interaction in failure scenarios, and it looks like
mkimage will have to be patched in case this doesn't just go into
full.cz under some sort of conditional check.