Rename external_file hash json attribute to data_hash
Conflicted with the ruby hash method
Allow login with all DNs.
Does not add any extra permission. External services are authorized here already:
https://github.com/opinsys/puavo-users/blob/a4a8483ba8ac4cf1e8510c4b39b6e7f243b9ed93/lib/puavo/authentication.rb#L223-L227
Puavo Authentication: Extract uid->dn conversion method