LDAP login with multiple attributes

Problem to solve

Currently it is not possible to use different LDAP attributes for authentication. It would be great if users could use different LDAP attributes (e.g. sAMAccountName,uid,, userPrincipalName or mail) and their password, which all point to the same user.

Intended users

A login process using the email address and the uid or sAMAccountName is probably desirable for all GitLab users with LDAP-Backend.

User experience goal

Users can login by several LDAP attributes to the same account.

Proposal

Enable omniauth-ldap custom-filter as described in: https://github.com/omniauth/omniauth-ldap