js/loader.js: preserve scrolling position...

...on autorefresh and reset it otherwise.

fixes #6285
fixes #6988

public/js/icinga/loader.js

@@ -665,7 +665,11 @@
             var self = this;
             var containerId = $container.attr('id');
             if (typeof containerId !== 'undefined') {
+                if (autorefresh) {
                     scrollPos = $container.scrollTop();
+                } else {
+                    scrollPos = 0;
+                }
             }
 
             var origFocus = document.activeElement;