Support LDAP login based on sAMAccountName instead of the email

[anuviswa]

Preflight Checklist

• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for an issue that matches the one I want to file, without success.

Problem Description

Is there a way to login a user based on the sAMAccountName instead of the email id using the LDAP connector? There are many legacy customers who would like to logon users using their configured sAMAccountName.

Proposed Solution

Support LDAP login based on sAMAccountName in addition to email based login.

Alternatives Considered

No response

Additional Information

No response

[jsquyres]

We would be happy to create a PR for this functionality if the Dex community would be interested in it. Should we do so?

@nabokihms @sagikazarmark Similar to #1058 (comment), I'm pinging you because it looks like you both have recent commits in Dex, and you are both listed in MAINTAINERS.