GitLab

This triggers unnecesary authentication prompts

BUG: 429406

As reported in https://bugs.kde.org/show_bug.cgi?id=328616, when a user
accepts an invitation to an event, when it is loaded on Google Calendar,
it creates a new event with the user as the organizer. To prevent this,
the "import" API should be used instead of the "insert" API.
With this change, the organizer is checked against the account name of
the user: if they match, the event is created (previous implementation),
otherwise the event is imported ("import" API).
This still requires some tests to check if it does not break anything.

BUG: 328616
FIXED-IN: 5.17

Allow to use UNITY build see https://cmake.org/cmake/help/latest/prop_tgt/UNITY_BUILD.html (Reduce compile time. Need cmake 3.16.0)

In the current Google tasks api
https://developers.google.com/tasks/reference/rest/v1/tasks#Task
the "due" field only contains date information;  the time portion is fixed
at 00:00 UTC.  Treating it as a meaningful UTC date-time causes KOrganizer
to display the task at an arbitrary time, and probably on the wrong day.
Treating Google tasks as all-day tasks works around the problem.

KIO::AM provides integration with KDE-wide cookiejar, which is useless for us
as we do not use cookies while talking to Google. Using QNAM gives us exactly
the same features we need minus dependency on KIOWidgets framework.