Update nova content for Juno

I updated nova content in the installation guide for Juno
as follows:

1) Removed prompts specific to MySQL because most distributions
   will use MariaDB.
2) Explicitly created endpoint with 'regionOne' region to avoid
   inconsistent defaults.
3) Replaced 'auth_*' keys with 'identity_uri' key.
4) Moved glance configuration to [glance] section.
5) Recommended enabling verbose logging.
6) Added example command output and updated existing command
   output.

Change-Id: Iad5c20e6562bcab83c6f0d5efccab566b3c18eae
Merge "Update nova content for Juno"