Console: /configlogging fixes

Add UI for enabling log compression (requires routerconsole.advanced)
Don't save and display override changed message unless overrides changed
Only call ctx.logManager() once in helper/handler

core/java/src/net/i2p/util/LogManager.java

@@ -696,12 +696,19 @@ public class LogManager implements Flushable {
     }
 
     /**
-     *  @since 0.9.56
+     *  @since 0.9.56, public since 0.9.57, was pkg private
      */
-    boolean shouldGzip() {
+    public boolean shouldGzip() {
         return _gzip;
     }
 
+    /**
+     *  @since 0.9.57
+     */
+    public void setGzip(boolean yes) {
+        _gzip = yes;
+    }
+
     /**
      *  @since 0.9.56
      */