Adding account to team without user fails with ds=1

[vmcj]

Description of the problem

Given datasource=1 & a team without an account. It is not possible to use the Add user to this team > Create new user
I suspect because we don't have a field for external ids and don't autocreate one.

[nickygerritsen]

We should probably set the external ID to the username here.

[meisterT]

One more reason to clean up the data source mess

[nickygerritsen]

It seems the whole 'add user to team' for existing teams doesn't work. @vmcj changed the logic to show this field but we never created the user. I will implement this.