Describe the bug

1. When I register for a meeting and I have "email notifications" de-activated on my account I don't receive an email with the registration code for the conference.

2. I should receive a code with that code, or display it when I register, or, at least, I should receive a notification. Ideally I should be asked how do i want to receive the code when I am registered, and maybe I should even be asked if I want to be contacted further by mail about the results (independently of regular newsletters or notifications). As a temporary shortcut to the ideal solution at least I should receive a notification for the meeting. It is otherwise impossible to access it. My code should/could also be displayed under the registration button once I am registered because notifications can be deleted and cannot be recovered and we don't want participants not to be able to access they registration code for a meeting.

If a participant is a regular user of Decidim, she will most probably have the "email notifications" de-activated on her configuration, because you otherwise get dozens of notification emails per day. These users don't deserve not to get their registration code :)

https://meta.decidim.org/processes/bug-report/f/210/proposals/13406