Reimplemented XML Tools and added styling (#227)

Co-authored-by: Adam Bem <adam.bem@zoho.eu>
Reviewed-on: #227
Reviewed-by: Mikolaj Widla <widlam@noreply.example.com>

Frontend/src/assets/sampleXQuery.xquery

@@ -0,0 +1,7 @@
+declare namespace p="http://www.release11.com/person";
+declare namespace b="http://www.release11.com/book";
+declare namespace l="http://www.release11.com/library";
+
+
+for $x in //p:person
+return string($x/p:name)