Sometimes users want to receive email notifications of messages they create or reply to,
Added an option to personal preferences to allow users to choose
Closes#20149
* Use email_address table to check user's email when login with email adress
* Update services/auth/signin.go
* Fix test
* Fix test
* Fix logging in with ldap username != loginname
* Fix if user does not exist yet
* Make more clear this is loginName
* Fix formatting
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>
Lunny Xiao
Tyrone Yeh
Johan Van de Wauw