detect http:// or https:// in the redirect URL for off-domain redirects

so that it supports redirects to other websites

example 

```
<RoutingRules>
  <RoutingRule>
    <Redirect>
      <Protocol>https</Protocol>
      <HostName>myaccount.signin.aws.amazon.com</HostName>
      <ReplaceKeyPrefixWith>console/</ReplaceKeyPrefixWith>
      <HttpRedirectCode>301</HttpRedirectCode>
    </Redirect>
  </RoutingRule>
</RoutingRules>
```
