add feature to allow change of username

[tingox]

a number of our users have used their email address as username in p2k16. This is a privacy issue, as your p2k16 username gets exposed several places (example: "Recent events" log in p2k16, contributions logs in the wiki). Due to a bug in the p2k16 / wiki interface users with an email address as the username can't login to the wiki - another issue, but bad as it prevents those user from contributing to the wiki.

Proposal: add feature to p2k16 that allows a user to (or an admin) to change the username of a user in p2k16.

If the proposal fails to be implemented, we should
a) prevent user from using an email address as a username when registering in p2k16
b) manually go through the p2k16 database, make a list of "email as username" users, and manually change the username in cooperation with each user.

[tingox]

Some data: currently 1698 users are registered in p2k16. Of these, 320 have an email address as username (technical: they have the character '@' somewhere in their username). So that is about 18.8 % of the users in p2k16. No attempt has been made to figure out if these are active users.

[mastensg]

the sign-up page also has a convenient "use email as username" button

[mastensg]

[tingox]

Perhaps we should start by removing that link?

[tingox]

Dette er fortsatt en aktuell problemstilling: hvis vi gir brukere mulighet til å endre brukernavnet sitt (fra "epost-adresse som brukernavn") så kan Bitraffere som er interessert i å bidra på wikien endre brukernavnet sitt, logge inn på wikien og bidra.

[tingox]

also: Mediawiki converts underscores to spaces, so people who have an underscore (example: user_name) in their username can not logon to Bitrafs wiki.