Add missing configurations and examples for a staging server deployment

1. A staging environment config was added (currently just a copy of the production environment, but this can be used as a starting point for staging configurations).
2. Add the default `admin@local.host` account to the staging database.
3. Show the appropriate log file (e.g. staging.log for staging, production.log for production, etc) in the Admin Log Viewer page.
4. Adjust example config files as necessary with a staging config.