Support OSGi R7 factory configurations with factory PID and name

[oliverlietz]

104.7.2 Creating a Managed Service Factory Configuration Object:

[...] The ConfigurationAdmin class provides the following two methods allowing the caller to influence the generation of the PID when creating a new Configuration for a Managed Service Factory. The PID for the Configuration object is generated from the provided factory PID and the provided name by starting with the factory PID, appending a tilde ('~' \u007e), and then appending the name. The getFactoryConfiguration methods must atomically create and persistently store a Configuration object if it does not yet exist. [...]

See also KARAF-6676