setup password for internal database config

- both internal and external prompt for user credentials
- move database config into common area
- don’t show (none for non default) if no default password
- use md5 for all network connections (no ident installed)
- allow cli to pass in username/password
- configure CentOS appliance with default password

https://bugzilla.redhat.com/show_bug.cgi?id=1128291
Merge pull request #372 from kbrock/postgresql_auth

setup password for internal database config