Investigate putting users in a single none group

[diegoalzate]

overview

when users do not have a group they join a group called none, which is basically grouping them. we need to investigate what side effects positive or negative would it have to group the users into a group by themselves by default.

[MartinBenediktBusch]

No side effects. Actually it is probably the correct thing to group the user into a group by themselves by default. So if a user selects 'None' we need to autogenerate a affiliation that is unique and put the user there.