Remove date of birth and gender from database

[rbaltrusch]

Currently there is no real need to store the date of birth or gender of users in the database, except for the fact that this data is handily available when the database data is generated.

Asking for date of birth on user registration is likely a violation of common data protection laws to avoid storage of unnecessary user data.

However, given that the data is currently not required to open an account, asking for 'date of birth' and 'gender' may be fine and could stay.