Extract EE specific files/lines for lib/gitlab/auth

We have the following files containing EE specific code. We should move them to ee/

• lib/gitlab/auth/ldap/access.rb
• lib/gitlab/auth/ldap/config.rb
• lib/gitlab/auth/o_auth/user.rb (We just need to add a missing blank line in EE!)
• lib/gitlab/auth/saml/config.rb
• lib/gitlab/auth/saml/user.rb
• lib/gitlab/auth/user_auth_finders.rb