Anaconda needs enough space to download the rpms and install the packages
when running livemedia-creator with virt mode so the / partition needs
to be larger.
Resolves: rhbz#1973407
Also add comments to the top of the example kickstarts describing how
they are meant to be used and providing an example cmdline. In some
cases, like rhel-minimal.ks, it can also be used for a live-iso but
requires a couple of extra packages for that to work.
Resolves: rhbz#1730937
