Redirect to registration

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | ---
| Fixed tickets | ---
| Refs tickets  | #901, https://github.com/zikula-modules/OpenID/issues/1
| License       | MIT
| Doc PR        | ---

Authentication modules now can implement a new function named `redirectToRegistrationOnLoginError()` to indicate whether or not the user should be redirected to the registration page if the given credentials on login are wrong. This is useful for the OpenID module. If you click "Login with Google", and don't have an account, you are redirected to the registration page. I'll push the changes for OpenID in a minute.