Use mock resultdir to pass parameters to mockyumconf.

The parent process environment is no longer accessed by mockyumconf
module.
Check if implantisomd5 command is available.
Export CHROOT_SETUP_CMD to mock environment.

You can set the chroot_setup_cmd parameter for mock in your config
file.
Create kickstart files in output dirs.

Added syslinux requirement.
Added build-iso -s, interactive shell flag.

The chrootscript.sh now uses default repositories configured by
MOCK_YUMCONF parameter.
Changed project URL to nethserver.org
Fixed italian lang label. Refs #1757
Interactive installer: fix spare option on systems with 2 disks. Refs #1757
Interactive installer: change RAID_2_DISKS label. Refs #1757