Study manager

When creating new user, a username should be pre-filled with probable value of new username.

More specifically, it should be possible to create users based on pattern such as doctor$NUM, admin$NUM.

Concrete patterns of usernames can be extracted from:
- history of created users (e.g. In case where doctor2 was last created user, we can look for MAX=maximal number, where username doctor$NUM exists. Then for new username we can assign doctor${MAX+1} )
- a role that is selected within "create-user form" (thus look for last username of same role as the selected one)