title: How can I get other users info(username, firstname) by id? [Keycloak]
body: <p>How can I get user keycloak attributes (username, firstname, email...) based on user id? 
  The user I'm using in the Keycloak session has already the role <i>view-users</i> assigned so I should be able to list at least all users, is there any Keycloak class that I can use?</p>
  
  <p>What I'm trying to achieve here is to avoid to replicate the keycloak users database to another local database, but doesn't seem possible to access any other user info, besides the one in the current session...</p>