Previously, it copied an internal Akonadi url (i.e. akonadi://?item=...),
which isn't recognized with KJots. Use newly introduced KJotsModel::UrlRole instead.
The pasting code (KJotsEdit) did not cope well with unicode
(it was converted to QLatin1String before pasting), fixed that as well.
Also, used QStringLiteral instead of QLatin1String for methods that don't have QLatin1String overload.