Install Guide: Cleanup for ch_basics

Cleanup usage of os to use only the right tags (for example only "sles"
for a SLES section)
Fix some screen sections to display better
Install openstack-utils on openSUSE/SLES
Fix typos

Change-Id: I031ae4102eee12a69eb1a4271f563866123ba980
Merge "Install Guide: Cleanup for ch_basics"