Implement get and create event features

[urmade]

Description

Use #2 to create a new app and get existing events. All payload information for the create functionality will be provided externally, so provide an API schema for this. Implement a functionality to optionally create a teams meeting for the event. This should also be returned when getting an event. GET should work with a calendar id or an event id.

[MalteRei]

API calls for graph:
Create new event
ForEach campus in organizers
POST /users//calendars/{campusCalendar}/events
PATCH /users//calendars/{campusCalendar}/events (with extension data)
AND
POST /users//calendars//events
PATCH /users//calendars//events (with extension data)

Get all upcoming events
GET https://graph.microsoft.com/v1.0/me/calendar/events?$filter=start/dateTime gt '{today}'&$select=campus-community_commastoEvents,id
AND
Filter to all objects that contain an attribute campus-community_commastoEvents

[MalteRei]

Admin principle is a dummy account. By using the Resource Owner Password Credentials flow the admin principle creates all events