disable byoc in provisioning (NVIDIA#327)

* disable byoc in provisioning

* add more comments on how to enable byoc

examples/cifar10/workspaces/secure_project.yml

@@ -9,6 +9,8 @@ participants:
     org: nvidia
     fed_learn_port: 8002
     admin_port: 8003
+    # `enable_byoc: true` would allow loading python codes in app.  Default is false.
+    # Needs to be enabled for each site if desired. Also enable `allow_byoc` for your admin group below.
   - name: site-1
     type: client
     org: nvidia
@@ -62,8 +64,8 @@ builders:
         relaxed: 
           desc: org group with relaxed policies
           rules: 
-            allow_byoc: true
-            allow_custom_datalist: true
+            allow_byoc: false
+            allow_custom_datalist: false
       disabled: false
   - path: nvflare.lighter.impl.cert.CertBuilder
   - path: nvflare.lighter.impl.he.HEBuilder