SignUp policy examples missing

[lsmith77]

The examples only cover SignUpSignIn but not the SignUp policies. It would be great to at least provide one example of this.

Context:
We have some use cases where we know users will not yet have an account. The SignUpSignIn user flow defaults to offering a login and not a signup form, which can confuse users. So for these use cases we want to send them directly to a SignUp flow only (we will then add a link in our template to the SignUpSignIn flow if they do have an account).