Meetings: start and an end date for registration + a waiting list

Is your feature request related to a problem? Please describe.
Many of OSP's partner organisations are using external tools to manage the registration for meetings on the platform. However, this leads to users leaving the platform without exploring it much, and a not-ideal user experience as they have to hop from page with the risk of getting lost.

Describe the solution you'd like
One of our proposals - allowing registration for meetings without an account was accepted. While working on it, we realised that much more can be done to make meeting registrations on Decidim - better. After discussions with several cities such as Toulouse, we got two key improvement points:

• having a start and end date for registration to meetings - similar to forms.

• having the option to have a waiting list for a meeting - if all slots are filled, and someone unregisters, automatically give the spot to someone that was waiting.

Describe alternatives you've considered
Using external meeting registration services, but as mentioned that's not ideal.

Does this issue could impact on users private data?
No

Funded by
Possibly yes.