form: fix contact details/profile application when using email

confirmation

my rewrite of account-creation stuff had a massive oversight of email
confirmation, the steps done after account creation (email and contact
method storage, referral stuff) were not done on the email confirmation
path. This has been factored out to PostNewUserFromIvnite, and the
ConfirmationKeys store now includes the newUserDTO and the list of
completeContactMethods.

models.go

@@ -455,3 +455,14 @@ type CreateBackupDTO struct {
 type GetBackupsDTO struct {
 	Backups []CreateBackupDTO `json:"backups"`
 }
+
+type ConfirmationKey struct {
+	newUserDTO
+	completeContactMethods []ContactMethodKey
+}
+
+type ContactMethodKey struct {
+	Verified bool
+	PIN      string
+	User     ContactMethodUser
+}