This adds CalDAV support for app generated calendars,
which are registered to the nextcloud core.
This is done by adding a dav plugin which wraps
all ICalendarProviders into a Sabre plugin (inspired by the deck app).
Add unit test for AppCalendar wrapper plugin and calendar object implementation.
Signed-off-by: Ferdinand Thiessen <rpm@fthiessen.de>
Anna Larch
Andy Scherzinger
Ferdinand Thiessen
Christoph Wurst
Mattia Narducci