emails: automatically fix typos in email addresses.

Try to automatically fix various kind of typos and common mistakes in
email addresses when a user creates a new account. It's common for users
to signup with addresses like `name@gmai.com`, which leads to bounces
when we try to send the welcome email.

config/initializers/types.rb

@@ -1,3 +1,4 @@
 Rails.application.reloader.to_prepare do
   ActiveRecord::Type.register(:ip_address, IpAddressType)
+  ActiveRecord::Type.register(:email_address, EmailAddressType)
 end

config/locales/en.yml

@@ -69,6 +69,7 @@ en:
         uploader: "You"
         uploader_id: "You"
       user/email_address:
+        address: "Email address"
         normalized_address: "Email address"
       user_feedback:
         creator: "You"