Fix osgi imports because of shade plugin relocation

Fixing OSGi manifest imports/exports.
maven-bundle plugin runs in process-classes phase and shade plugin runs later and relocates jackson and apache commons classes.
Should ignore relocated packages as they are inlined in the bundle and also no need to import packages from parent bundle i.e. ch.qos.logback.classic.  Let parent manage imports of logback core and slf4j versions.
Added export of net.logstash.logback.appender package as documentation provides an example for its usage.