SLF4J is a commonly used abstraction for various logging frameworks
such as java.util.logging (JUL) or Log4j. Currently, plugins are
required to do all their logging using the provided JUL logger.
This is annoying for plugins that target multiple platforms or when
using libraries that log messages using SLF4J.
Expose SLF4J as optional logging API for plugins, so they can use
it without having to shade it in the plugin and going through
several layers of logging abstraction.
