Added DemoUtil for common Demo operations and misc updates

1. Aded DemoUtil. Its static setup() method loads Config file (with
appKey) and Logger settings file (Logging.properties)
2. Updated all DemoZZZ services to use DemoUtil.
3. Added config.properties template file with APP Key property
4. Updated services implemented in Sprint 4: branch by Id, etc.
Added config.propeprties file to support appKey configuration