Reorg tutorials to match nav, and update links

docs/tutorials/python/modular-tutorials/index.md

@@ -0,0 +1,15 @@
+---
+html: modular-tutorials-in-python.html
+parent: python.html
+top_nav_grouping: Article Types
+metadata:
+  indexPage: true
+seo:
+    description: Modular XRPL tutorials in Python.
+---
+# Modular Tutorials in Python
+
+These tutorials take an incremental approach to implementing functionality, so you can reuse parts from the earlier tutorials on your way to making more advanced software.
+
+
+{% child-pages /%}