Campaign: Member coordination in the app

[JuliaFreitagBGSt]

Is your feature request related to a problem? Please describe.
Members are currently sharing lists in the Grüne Wolke to coordinate the campaign and the members, but these wolke-lists only work very poorly via browser, especially on cell phones.

Describe the solution you'd like
It would be desirable to be able to plan staff for the election campaign in the app. The following functions would be necessary: assignment of rights, who can set appointments and for which election campaign form; filter function according to OV and KV.
Also Appointments: Which election campaign form, meeting point, date, time (start and optionally end time); it would also be ideal if you could set the minimum number of experienced people needed (especially for HTWK and WKS) as well as text/instructions (e.g. which streets will be made or whether something else needs to be brought along, etc.). Then the people can use the app to enter their experience for each type of campaign and book themselves for appointments.

Describe alternatives you've considered
Alternatively, this could be developed in the atlas and would only be displayed in the app and only appointments could be confirmed in the app.

Additional context
This is something for later (Release 3), when the Atlas is further developed.

[JuliaFreitagBGSt]

Created an Issue in gruenes-netz-admin (#61) and gruene-api (#138) as well.