Add release_notes for version 1.9.0
Add release_notes for version 1.9.0

git-svn-id: fac53d8b196e0ef1c2775236b39a8c3227ab71b5@945 528793b8-127e-4309-9901-b74759c7208d

OpenConext/OpenConext-serviceregistry,OpenConext/OpenConext-serviceregistry