Show email address of user in the account

[KlausIllmayer]

Currently, users can't see which email address they shared when they registered their account. It would be good, that they can see this email somewhere in the account, so that they can send us an email that their email-address has changed.

The email address is given in the api/auth/me-call so it is more a matter of where to put this information.

The next step would be that users can change their email, but for this we need an API call, see SSHOC/sshoc-marketplace-backend#456

[laureD19]

Add the information to the /account page in the welcome message description.