nomodeset no long does anything helpful, and inst.text doesn't make sense
with a live image so drop the menu from the live image.
Related: rhbz#1961092
...turns out you can't just have a single template file, because lorax
just picks a single directory and expects all the data it needs to be
there. Sigh.
So this adds all the rest of the files, plus some Makefile machinery for
generating a tarball and updating the specfile after you've checked in
changes. See README for details.