Add Kiwi config and build script for Pebbles (SLES 11 SP3) dev VM

- Completely cleaned up the Kiwi export from http://susestudio.com,
  which contained a lot of things that we don't need.

- Added lots of documentation to config.xml, so it's easier to
  understand and maintain.

- Tested that resulting VM contains all needed SUSE Cloud packages, and
  running `/opt/dell/bin/install-chef-suse.sh` runs all the way to
  completion with web UI working!

- The Kiwi config should eventually live in IBS/OBS so we get automated
  and continuous builds.
Add a nice /etc/motd

ASCII banner from http://www.network-science.de/ascii/:
- Font: small, Reflection: no, Adjustment: left, Stretch: no,
  Width: 80, Text: Crowbar 1.6 Pebbles
Add tftpboot config

- Add /srv/tftpboot/discovery/pxelinux.cfg/default
- Add compatibility link to /srv/tftpboot (part of Crowbar package)

Moved from install-chef-suse.sh. Needed to make the provisioner work.
Add Cloud-PTF repo skeleton

Moved from install-chef-suse.sh. Needed to make AutoYaST happy.