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/spring-framework-5.3.23/README

@@ -0,0 +1,8 @@
+Spring Framework (https://spring.io/projects/spring-framework)
+--------------------------------------------------------------
+
+    Version: 5.3.23
+    From: 'Spring' (https://spring.io/)
+    License(s):
+        Apache v2.0
+