This adds a new livemedia-creator argument, --extra-boot-args, which can
be used to add arguments to the kernel command-line in the templates.
(cherry picked from commit a710d17294)
Related: rhbz#1690068
When using the template install command copying the same file to itself
shouldn't crash. Just log the error and continue.
Also copy the s390 configuration files for use with livemedia-creator
Resolves: rhbz#1269213
