Do not use os="..." in Cloud Admin Guide

The Cloud Admin Guide does not profile for the os variable and thus
all occurences of os=... are shown which leads to confusion. Add proper
wording for all examples.

Change-Id: Ib6a651dcfe23cbaad7b727658813c14f36aea73b
Closes-Bug: #1232864
Add debian to build commands for Install Guide

Change-Id: I13d2eccb0e9c5b85a7d63f04afa0033891e6afd7
Adds introductory text about the Image service for Install Guide

Change-Id: I93c900718bcf5c5875687d4ddd3a993da3832d71
Merge "Add debian to build commands for Install Guide"
Merge "Adds introductory text about the Image service for Install Guide"
Merge "Do not use os="..." in Cloud Admin Guide"