Update users by user list upload

[janno42]

It should be possible to update all UserProfiles by uploading a list with usernames and emails (which in each line contains a username, a ,, and the email address of this user). The username should not be used but is included in the list for historic reasons.
For all existing users the email address should then be updated if a match is found that only differs in the domain, if both the old and the new domain are defined as "internal domains" in the INSTITUTION_EMAIL_REPLACEMENTS setting.