Add change email action

[core23]

Feature Request

The user should be able to change the e-mail address.

This should be done with a multi step process:

• Always show a message to the user "A confirmation e-mail has been send", also if the e-mail is already in use. This is used to respect privacy, so you can't brute force used e-mail account of other members
• Sending an e-mail to the new address. Either inform the user that this e-mail is already be used by user "XY" or create an confirmation link
• The user must verify this address

[core23]

Moved this feature request to the ProfileBundle: nucleos/NucleosProfileBundle#2

This bundle should just support the basic features for user management. Changing auth information is more complicated if you want to respect user privacy.

There are also use cases where the e-mail can't or should not be changed.