Add file templ: QObject, QAbstractItemModel, QWidget, QDialog (pimpl & not)
Summary:
Having templates for both private and public API (pimpl or not) versions for
subclassing common base Qt classes helps to speed up creation of new code.
Reviewers: KDevelop, mwolff
Reviewed By: KDevelop, mwolff
Subscribers: mwolff, kdevelop-devel
Differential Revision: https://phabricator.kde.org/D9063