Fix some links to download.qt-project.org

Change-Id: I313ea0062e8a40cfc4cc6af1a0d2bb623476eedd
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>
Fix incorrect mimetypes for Qt Creator .desktop file

Change-Id: I09395436a01306be333dfd4600156ff6c30d7d89
Reviewed-by: Iikka Eklund <iikka.eklund@digia.com>