Use email as user-name for basic auth?

[poVoq]

Is your feature request related to a problem? Please describe.
Some services do not have a concept of a user-name and just use email as the login name. This makes it impossible to use them with this addon's http-basic auth.

Describe the solution you'd like
It would be great if the http-basic auth had an option to send the email as the username for external login instead and then use the name part of the email (name@example.com -> name=uid) as the uid in Nextcloud. Nextcloud already has the option to allow people to log in with their email instead of the user-name, so that would map well I think.