Mongo Atlas doesn't support some characters in username

[eliasscosta]

Hi,
Mongo Atlas doesn't support some characters in username like @ and .. In my use case the DisplayName is from a kubernetes jwt and has this structure name.lastname@site.com, when plugin create a username they put this characters and we receive a error from Atlas API.

One solution, before submit to Atlas API encode the username to base64, to prevent this issue.