Add EndTime and Ical attributes to Event
Summary:
EndTime is necessary for the implementation of the calendar UI in Kube.
Fixes T8482
Ical to mimic Mail's MimeMessage attribute.
(Sorry for the wait, there was a good number of merge conflicts when rebasing on develop)
Reviewers: cmollekopf
Reviewed By: cmollekopf
Tags: Sink
Maniphest Tasks: T8482
Differential Revision: https://phabricator.kde.org/D12085