Fix kiwi config for openSUSE 12.3

Force module-init-tools to be installed, otherwise zypper would automactically
choose kmod-compat which would lead to a conflict with kernel-default later on.
Updated descriptive info and documented where it leaves the generated
Sledgehammer data files.
Merge pull request #1766 from rhafer/fix/kiwi-12.3

Fix kiwi config for openSUSE 12.3
Merge pull request #1767 from cloudsleuth/pull-req-master-ae72b6b0e4046381045e79f54e9d194fd35e639a

Sledgehammer README update. [1/1]
include comment showing how to create admin node