SLING-3257 - Make logback packaging data in stacktraces configurable

Added property `org.apache.sling.commons.log.packagingDataEnabled` to configure the
packaging data support. By default it would be enabled

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1546601 13f79535-47bb-0310-9956-ffa450edef68