#Feature-Add: Email Validation

[gtandersen]

List of signup related issues in process order:

• [x] Decrease size of initial index sync modal that currently overlays the welcome offer: https://github.com/runbox/runbox7/issues/1509
• [x] Ensure welcome email is visible in the Inbox upon signing up
• [ ] Clarify that the alternative email address must be validated on https://runbox.com/app/welcome?postSignup=offer (although an email is automatically sent to the submitted address)
• [ ] No indication on https://runbox.com/app/account/details or https://runbox.com/mail/account that the alternative email address has been validated
• [ ] No information or link to validate alternative email address from https://runbox.com/app/account/details
• [ ] The email validation link that is sent takes the user to Runbox 6 instead of 7
• [ ] Show a warning upon login if the alternative email address has not been validated