Feature: Notifications

[juzim]

Is your feature request related to a problem? Please describe.
I'd like to get a notification if a new wish is added, claimed or deleted in my group.

Describe the solution you'd like
For now, an email notification would be sufficient. A push URL would be a quick solution for more services, but ideally there would be an apprise integration.

A setting section is required per user and an admin settings page if not handled by environment variables.
In the future, it might be useful to be able to explicitly follow wishes or lists.

Describe alternatives you've considered
A modular system to add multiple services. Might be easier in the beginning and require less setup from the users but will require an implementation and setting for each service.

Additional context