Auth service: Can't get user by email alias

Check with the auth service what are the alternatives and solutions.
We are using the api /api/v1.0/Identity/by_email/{email} which is returning nothing if we try to retrieve by email alias, which leads to invalid mapping of users (and duplicates)

Eg. My official email is carina.oliveira.antunes@cern.ch and my email alias is carina.antunes@cern.ch

Note: lowercase will be handled on #148 (closed)

Resolution:

• Authz Service will implement something soon (discussion with Paolo).
• Until then let's add a LDAP query to xldap.cern.ch (no auth needed) to resolve those mail addresses @cern.ch