Allow secretariaat to update primary_email

Signed-off-by: Bas Westerbaan <bas@westerbaan.name>
Secr. update e-mail address suggestions of Jille

Signed-off-by: Bas Westerbaan <bas@westerbaan.name>
Merge pull request #111 from khandhas-infra/update_primary_email

Allow secretariaat to update primary_email
find_name_for_user: do not break on users without names

Signed-off-by: Bas Westerbaan <bas@karpenoktem.nl>