The Spring team discourages the use of the `spring.*` configuration
namespace, hence I use the major update and move all properties. With
this commit all client related properties are moved to `sbadmin.client`.

Added documentation and a sample on how to secure the SBA-Server and
leverage the new login ui-module

closes #361

With this change it is possible to include credentials in the instance
metadata which will then be used to access the client endpoints using
HTTP Basic authorization.

closes #359