Extend example with dynamic properties

[mbe24]

Provide multiple implementations to service and use dynamic properties to determine "right" implementation.

• https://thecarlhall.wordpress.com/2010/06/06/set-osgi-service-reference-target-through-configuration/
• https://stackoverflow.com/questions/37940008/how-to-dynamically-update-references-in-an-osgi-component
• http://enroute.osgi.org/doc/217-ds.html
• https://stackoverflow.com/questions/10356226/dynamic-target-queries-in-osgi-with-ds

[mbe24]

• Rename service to service.api
• Create service.impl2

[mbe24]

Update properties of (ManagedService in) component with https://osgilook.wordpress.com/2009/03/22/configuration-admin-service-explained-the-managedservice-interface/