Add Functions secrets management tutorial

Author: deepganguly

articles/container-apps/TOC.yml

@@ -215,7 +215,9 @@ items:
         - name: Create a Functions app through the portal and CLI
           href: functions-usage.md
         - name: Manage a Functions app
-          href: functions-manage.md 
+          href: functions-manage.md
+        - name: Manage secrets for Azure Functions on Azure Container Apps
+          href: functions-secrets-tutorial.md
         - name: KEDA scaling mappings reference
           href: functions-keda-mappings.md      
         - name: Migrate from Functions v1 to v2