Magic link authenticator extensible solution

[rtufisi]

Inspired from https://github.com/sventorben/keycloak-home-idp-discovery/tree/main/src/main/java/de/sventorben/keycloak/authentication/hidpd/discovery/email.

Make AbstractMagicLinkAuthenticatorFactory where we have a basic logic of sending the magic link email. It should contain a MagicLinkConfig class with the basic function to forceCreate

Create a custom MagicLinkCustomizationSpi in order to fit business need. Make it possible to have custom MagicLinkCustomizationConfig in addition to the base MagicLinkConfig.

Create a default implementation to have a default to the exiting logic and create a example of custom logic for the Organization use case.

[rtufisi]

@xgp