New feature for FAI.me service, set kernel cmdline options

[Thomas Lange]

Several people asked if it's possible to specify additional
kernel cmdline parameters in the FAI.me service. Now I've implemented
this feature. After toggling to the advanced settings, you can add
your options. These will replace the default "quiet" option.

This feature is currently only available for the installation images,
but not for the cloud images.
-- 
regards Thomas