Preview links on PRs are broken

[cazala]

Currently the preview urls in PRs are not working because it's not possible to log in.

The problem is that the redirect that the explorer-website does to /auth/login does not work, because the preview url is not hosted on decentraland.org but explorer-artifacts.decentraland.org. This can be fixed from the explorer-website side, but then the redirect that is done by the auth ui will not work, because the redirect url is explorer-artifacts.decentraland.org and it does not match the hostname of the auth ui, that is decentraland.org.

There are two ways I can think to fix this:

1. The first one is to create a path that redirects to the subdomain, like decentraland.org/explorer-artifacts -> explorer-artifacts.decentraland.org, that should fix all the issues mentioned above.

2. The other option is to make two changes, on the explorer-website and other on the auth ui.

• explorer-website: Fix the login redirect url so when it detects is being used on explorer-artifacts.decentraland.org it redirects to an absolute url decentraland.org/auth/login instead of a relative one /auth/login. That happens here.

• auth: Allow redirecting to subdomains of the hostname as well. So a login on decentraland.org could redirect to *.decentraland.org, and that would work with explorer-artifacts.decentraland.org. That can be done by replacing the redirectToURL.hostname !== window.location.hostname with !redirectToURL.hostname.endsWith(window.location.hostname) here.