no issue
- moved duplicated email domain generation from `members-email` controller and `<GhMembersEmailSetting>` to `config.emailDomain`
- added `{{from-email-address emailStr}}` helper that will output the passed in emailStr value if it contains an `@` or concat `emailStr@emailDomain` if it doesn't - lets us use `settings.membersFromAddress` to always get a full email address when it could be just a name (`noreply`) or a full address
- updated customise email and post email preview templates to use the new helper
