Remove magicAuthLink and passwordResetLink functionality from @keystone-6/auth

[dcousens]

This pull request removes the magicAuthLink and passwordResetLink functionality from @keystone-6/auth. The rationale is that this functionality is often unused and consequently unmaintained within the project.

While passwordResetLink functionality can be helpful, most projects I have seen have implemented their own versions, often finding the provided interface unsatisfactory. The community has shown that @keystone-6/auth does not adequately support this functionality, as seen in discussions like this one, leaving developers to write most of the feature themselves.

This change will reduce the complexity of the @keystone-6/auth module, which is a precursor to initiatives such as #8097.
#8097 and other initiatives seek to add support for advanced authentication methods (like MFA) and functionality to Keystone in a new and improved manner.

If you know of any projects that rely on these features and would be adversely affected by their removal, please share your experiences and use cases.

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[andy-blum]

I'm using this functionality on a project right now and would be sad to see it go.

most projects I have seen have implemented their own versions, often finding the provided interface unsatisfactory.

I'm curious what shortcomings people are seeing in this and what DIY systems they're building. If this functionality is removed, I'd hope to see a good replacement suggestion in documentation.

[dcousens]

@andy-blum fair point, maybe I can add an example to this pull request, and from there we can discuss how the example fairs compared to the inbuilt functionality.

[borisno2]

Looks good @dcousens - just put in a rough first pass example of a magicAuthExample without using the auth package in case that is useful