Add the user admin first name, last name and email in the starter input for SMTP conf

[jgrodziski]

For the SMTP configuration to work in Keycloak the admin account in the "master" realm must have the email, first name and last name filled. The starter doesn't take into account such data for the moment

Add a :user-admin key in the :realm entry of the starter input data structure with the following shape:

:user-admin {:username "admin" :firstname "John" :lastname "Doe" :email "admin@example.com"}