Edits to the Installation Guide Database section overview

Edits to clean up content

Change-Id: I05e587683deb2141915d379afaa54b2cb788d38c
Implements: blueprint installation-guide-improvements
Target Install Guide for Juno

Add note about the state, mark guide as targetting juno.

Change-Id: I772b6a3dfe8667a835d0151c30b0226a55e2856c
Merge "Target Install Guide for Juno"
Merge "Edits to the Installation Guide Database section overview"