fix: doubled log messages when SplitLogManager.configureHandlers is called twice (#1043)

Some classes call `SplitLogManager.configureHandlers` to make the prefix
quieter, _e.g._, `DatabaseConstantProvider`; this was causing log
messages to double. This PR fixes the issue, and adjusts the formatting
a bit to be more consistent with the database classes' log messages.

Author: c-dilks

common-tools/clas-logging/src/main/java/org/jlab/logging/SplitLogManager.java

@@ -45,13 +45,15 @@ public static void configureHandlers(Logger logger, boolean includePrefix) {
 
     // clear handlers
     logger.setUseParentHandlers(false);
+    for(var handler : logger.getHandlers())
+      logger.removeHandler(handler);
 
     // log message formatting
     if(includePrefix)
       // "[source] level: message throwable_backtrace\n"
       System.setProperty(
           "java.util.logging.SimpleFormatter.format",
-          "[" + logger.getName().replaceAll(".*\\.","") + "] %4$s: %5$s%6$s%n");
+          "%4$s: [" + logger.getName().replaceAll(".*\\.","") + "] %5$s%6$s%n");
     else
       // "level: message throwable_backtrace\n"
       System.setProperty(