Remove KContact::Geo QObject wrapper for Grantlee

Summary:
No longer needed, as KContact types can now be consumed directly for this.
There's minor behavior differences (e.g. regarding return values for
invalid coordinates), but since no template seems to be using this that
shouldn't be a problem.

Reviewers: mlaurent

Reviewed By: mlaurent

Subscribers: kde-pim

Tags: KDE PIM

Differential Revision: https://phabricator.kde.org/D20538