Configuration API: Switch to config annotation types instead of ValueMap

as proposed on the sling mailing list by carsten a refactoring of the API for accessing configuration values would be useful: use an annotation type instead of a ValueMap.

example:

and accessing the configuration:

perhaps we can even find a way to combine both steps in a single step, bypassing the Configuration.class or making its use optional.

this is a major and incompatible refactoring of the API, but because none of the APIs have an 1.0 release we can still do it.