java.util.logging logs now follow the XWiki logging configuration

Some libraries used by XWiki, like Lucene (the search engine behind Solr), produce their logs with java.util.logging. These logs now go through Logback like the other XWiki logs: they use the same format and destinations, and their levels can be configured in the logback.xml file (see Logging). For example, on Java 21 or later, the Lucene message starting with Using MemorySegmentIndexInput is not displayed anymore when the embedded Solr opens its indexes, since it's below the default warn level.