Integrate SAML V2

Nuxeo Authentication system is pluggable and already provide indirect way to do SAML authentication via CAS2 or Shibboleth.

However, SAML V2 becoming a recurring question, it is probably useful to have a dedicated authenticator.

However, the problem is usually not only to integrate SAML V2, but rather to integrate a full IDM solution that provide a end to end solution for provisioning and managing users.

Such solutions include Okta, OneLogin or PingIdentity.

In addition of Authenticator and Login module, a full IDM integration may impact user management screens.