Added XQuery Tool and refactored tools-service (#220)

Co-authored-by: Adam Bem <adam.bem@zoho.eu>
Reviewed-on: #220
Reviewed-by: Mikolaj Widla <widlam@noreply.example.com>

Samples/xquery/xquery.json

@@ -0,0 +1,6 @@
+{
+    "data": "<people><person><name>John</name><age>67</age></person><person><name>Anna</name><age>69</age></person></people>",
+    "process": "for $x in //person return string($x/name)",
+    "processor": "saxon",
+    "version": "3.1"
+}