5.0 Sample app RBAC update

The 4.6 sample needs an update to use RBAC, or it won't work when people upgrade to 5.0.

For each try-cb-xxx repo update doing the following:

1. Make a 5.0 branch
2. Update 5.0 branch with authentication changes
3. Put a note in the 4.6 README that points to the 5.0 branch to get latest changes
4. Master branch will remain working for 4.6 until 5.0 server launches, then we make a 4.6 branch and merge 5.0 into master.