Make 48h meeting reminder customizable

Is your feature request related to a problem? Please describe.
An automatic reminder is sent to registered participants of a meeting 48h before the meeting begins. In our practical experience, this is not ideal and lacks two degrees of customisation:

1. I might want to add additional context to the reminder (updated meeting information, additional details only for registered participants)

2. 48h before the meeting might not always be ideal. For some meetings, (i.e. such with a longer registration period), I would like to have a longer period, for other meetings, I might not want a reminder at all.

Describe the solution you'd like
Make reminder e-mail/notification customizable, namely with:

1. Checkbox, whether it should be sent at all

2. If yes, having the possibility to adjust the time of sending (in h) before the start of the event

3. Make the content customizable via text editor (as is already possible with invitation emails)

Describe alternatives you've considered
Using term customizer for each process for point (3.) might be an idea, but requires admin rights and doesn't always work as intended.

Additional context
This belongs to a series of meeting registration management improvements, which we are currently looking into:

• Waitlist for full meetings

• Allow meeting adresses to be unset/TBD

• Expand meeting notifications

Does this issue could impact on users private data?
No, as the data has already been collected and approval for contact granted.

Funded by
Maybe by the City of Zurich