Update AdminLTE

- from 2.4.5 to 2.4.18 (cannot detect any issues)
- set default scancycle for Apple Devices to 1

front/lib/AdminLTE/bower_components/bootstrap/less/close.less

@@ -1,3 +1,5 @@
+// stylelint-disable property-no-vendor-prefix
+
 //
 // Close icons
 // --------------------------------------------------
@@ -30,5 +32,6 @@
     background: transparent;
     border: 0;
     -webkit-appearance: none;
+    appearance: none;
   }
 }