[OSGi] Dependency documentation

The Log4j2-Core is a fragmented bundle. Apache Felix can not print unresolved dependencies of fragmented bundles. The fragmented bundle can not be resolved without any informations about required (transitiv) dependencies. Thus, ALL dependencies have to be documented.

E.g. the system-bundle has to load following packages with the bootstrap-classloader(FRAMEWORK_SYSTEMPACKAGES_EXTRA):
sun.misc,
javax.jms,
javax.mail,
javax.mail.internet,
javax.mail.util,
javax.persistence,
javax.servlet