Improvements to the organization authentication flow

[pedroigor]

I can create an issue for each of these points, but in general, they are polishing and adding more tests to the organization authentication flow. It also helps to use the CLI (WIP https://gist.github.com/pedroigor/5696da1f32370f32714fc61844fedec8) to start playground with organizations.

• Today, we are always redirecting users (regardless if they exist or not) to the broker associated with the org. Including when there is a single one. This change set makes sure users are automatically redirected only when:
• • If an existing user and already linked to the broker associated to the org
• • If a new user and there is a broker that maps to the email domain
• • If a user does not exist, the email maps to an org domain, and there are public brokers in the org, the registration link is hidden so that the user can register through the broker instead. A message is also shown.
• • Tests added for all those cases
• Fixes NPE when creating resources using the CLI where some optional data is not sent. It will help with working with the CLI
• Make sure the Sign in with message is not shown on login pages if there are no brokers to choose
• Not yet supporting internationalization

[ssilvert]

LGTM