Add customisation option for a registration URL

Description

I'd simply like to be able to show an option for users to register an account, redirecting to an external service.

Use Case

I've got a community that uses Authelia as it's SSO solution. New members do not automatically have an account created and needs to set it up through a web service, so I'd like to be able to easily direct them to that whenever they try to auth. This would be similar to the custom url option for password resets https://www.authelia.com/configuration/first-factor/introduction/#custom_url

Details

No response

Documentation

No response

Generative AI

No

Pre-Submission Checklist

• I agree to follow the Code of Conduct

• I have checked for related issues and checked the documentation