Rename and update secure hub-spoke network article

Author: mbender-ms

articles/networking/TOC.yml

@@ -32,6 +32,8 @@
       href: secure-application-delivery.md
   - name: Plan and design
     items:
+    - name: Design a secure hub-spoke network
+      href: design-secure-hub-spoke-network.md
     - name: Support for working remotely
       href: working-remotely-support.md
     - name: Virtual networks