[backend] more advanced email parsing

[siefkenj]

It looks like the valid_email2 gem could be used to parse email addresses before we send an email. This would allow more flexibility in how emails are entered into the email fields (e.g., the Name <[email protected]> format could be used--this format currently gives a mail error...).

See https://stackoverflow.com/questions/38611405/email-validation-in-ruby-on-rails for details