Add JDK Platform Logging (JEP 264) support

[tbroyer]

There are at least two dependencies with JDK Platform Logging support:

• slf4j-jdk-platform-logging
• log4j-jpl

This should probably be handled similarly to JUL (this is equivalent to jul-to-slf4j and log4j-jul respectively, with no equivalent to slf4j-jdk14), so it would a priori only need a slf4j-vs-log4j-jpl capability equivalent to slf4j-vs-log4j-jul.