Resolve "Prevent notification email replies to go to support@gitter.im"

Closes #2268 (closed)

The issue name has been changed to be more generic and to fit current fix implementation and so the MR name has changed as well.

The solution is to use the newly released interface of @gitterhq/env module https://gitlab.com/gitlab-org/gitter/env/merge_requests/25 and specify replyTo argument when sending out notification emails. env translates this argument to Reply-To email header and so the users who try to respond to the email will see they are replying to no-reply@gitter.im.

Testing strategy

(subset of https://gitlab.com/gitlab-org/gitter/env/merge_requests/25#testing-strategy)

1. checkout 2268-no-reply-notification branch
2. unlink the @gitter/env module from modules/env (if you've done it as a part of https://gitlab.com/gitlab-org/gitter/env/merge_requests/25#testing-strategy) (not sure whether this is necessary)
3. npm i
4. add mandrill secrets to your env https://gitlab.com/gl-gitter/secrets/blob/develop/webapp/prod#L6-7
5. run ./scripts/utils/send-unread-notification-email.js -u <username> -r <room uri> --dummy false
   • username and room uri need to exist in our local database
6. see that email inbox associated with username got a notification and when you try to reply to it, you are replying to no-reply@gitter.im