Rename the systemd and grub-efi .wks files to .wks.in, and replace all 'append'
entries apart from rootfstype (which is specific to the wks file) with
${APPEND}, so the values of APPEND from the BSP and user is respected.
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
