Using @Service without @Component should log a warning

If I use the annotation @Service without @Component no entry in the serviceComponents.xml will be generated and no warning is given out during build from the maven-scr-plugin.

You should either implicitly generate a component if @Service is given without @Component or an error should be logged during build, since using @Service without @Component right now has no effect at all and this is never intended by someone using @Service.