bp:restructure-documentation Restructure of Configuration Reference

Initial re-structure of guide (more is definitely needed, including
 edits, but can now work per component). Ensured all sections are
 consolidated under one of the services. Minor edits to work with
 structure flow. Redid guide intro to list all components. Added
 subdirectories for networking and compute (to match existing
 for block-storage and object-storage).

Change-Id: I7cf3ddbb48c201ac89b037daff786dfb7a22dd34