Enhance DS service to retrieve default hierarchy

The default hierarchy is now retrieved via the DS service. The default
hierarchy file 'default-hierarchy.xml' is expected to be in the same
folder in which the server is executed. If no such file is found, an
empty hierarchy with a correctly configured root is returned instead.

Change-Id: Ib99ff74f2c47618bfc76cc44f559065b91304ac7
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>
Change info message about host (issue #49)

Change-Id: Ia6bc66bf96a1572889ce0427f6b04ba0f4390082
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>