Create friendly message when trying to add users beyond license capacity

[bmicklea]

When a user tries to be added to a system that is at the user capacity dictated by its license:

• Do not allow the creation of the new user

• In a popup dialog print the following:

  Title: User Cannot Be Added
  Message: "The user cannot be added. You have {x} users in Codenvy which is the maximum allowed by your current license. Your administrator can add additional users by visiting Account > Billing in the Admin dashboard."
  Buttons: Ok

• The next time the Admin logs in pop up the following dialog box

  Title: Users Requesting Access
  Message: "Users have tried to access the Codenvy system, but you have {x} users in Codenvy already, which is the maximum allowed by your current license. You can add additional users by visiting Account > Billing in the Admin dashboard."
  Buttons: Ok

[bmicklea]

closed as duplicate