Feature request: Allow @ in username

[GlennMatthys]

Right now user accounts with the @ symbol in the username cannot be created. Since these days it's common to have email addresses double as username, it would be nice to maintain consistency and allow this.

[davidebeatrici]

The @ symbol is used to determine the user's virtual hub, we should probably add a setting to specify a different character.

[BlackHoleFox]

The : character may work?

[davidebeatrici]

Sure, but we should use @ as default in order not to break the login for updated servers.

[BlackHoleFox]

So it would be a config switch in the server between @ and :, with @ being the default?

[davidebeatrici]

Better: a config option to specify the character, with @ being the default.

[davidebeatrici]

Done.