KIS is an abbreviation for Kernel, Initrd, System and defines a
highly customizable image consisting out of these components.
This commit performs the changes documented in #1414 and
introduces the new kis type. From an image build perspective
kis is currently the same as pxe with restrictions for kis
on the schema level. A kis build uses dracut and does not allow
to use the legacy netboot initrd. The pxe type will therefore be
exclusively used to built for the legacy netboot infrastructure
and is on its way to deprecation in the future.
This Fixes#1262
e582651ee1