Graph: exclude default calendar in getSubCalendarFolders
Caldav: XML encode displayname on subfolders, only warn on missing items
Graph: add isDefaultCalendar property to calendar folders, specific implementation for getSubCalendarFolders
Graph: declare isrecurring field, adjust getCalendarItemCondition based recurrence and date condition, ensure urlcompname is always converted
Graph: implement getFreeBusyData
Graph: fix regression in handleRRule
Graph: refactor importance/priority handling, first try at recurrence handling on tasks: does not work on microsoft side
Graph: implement graph version of getTaskStatusFromVTodo and getVTodoStatusFromTask