GUACAMOLE-1594: Update all Java and JavaScript dependencies to latest compatible.

NOTE: Several WebPack plugins could not be updated as all plugins within
WebPack's "webpack-contrib" have dropped support for WebPack v4
entirely, but Closure Compiler only supports WebPack v4.

doc/licenses/datalist-polyfill-1.25.0/README

@@ -0,0 +1,8 @@
+datalist-polyfill (https://github.com/mfranzke/datalist-polyfill)
+-----------------------------------------------------------------
+
+    Version: 1.25.0
+    From: 'Maximilian Franzke' (https://github.com/mfranzke)
+    License(s):
+        MIT (bundled/datalist-polyfill-1.25.0/LICENSE)
+