Emails fail to send because SMTP username isn't an email address

[tomcollis]

Describe the bug
Emails fails to send because the SMTP username is used as the sender / from address.

To Reproduce
Steps to reproduce the behaviour:

1. Configure SMTP settings with a third party service (not Gmail)
2. For example, username of 'apikey' for (SendGrid)
3. Sign up as a subscriber and wait for verification email
4. Never received because of the invalid sender address

Expected behaviour
Either:

1. Separate field for from / sender address
2. If username doesn't contain @ symbol then show additional field for from / sender address

Additional context
Running v1.0.0. on Deta Space

[berrysauce]

Thanks for reporting this! I‘ll look into it!