Open-source release of Qt Design Studio

As communicated in the Qt Design Studio 1.0 release blog post, an open-source release of Qt Design Studio is targeted for December 2018 (see: [http://blog.qt.io/blog/2018/10/25/qt-design-studio-1-0-released/).] In practice, we want to release this in conjunction with QDS 1.1 to the extent feasible. Release should contain both a source package and binary installers (same platforms as the commercial one). 

The open-source release should not contain the following features:
 * Photoshop export/import
 * Live preview
 * ISO icon browser 

In place of these features there should be a note that these features are available in the commercial version.

User should be notified that when using the timeline animations the application contains a GPLv3 runtime component (i.e. designed asset becomes GPL when the timeline animations are used).

Otherwise the release content is same as the commercial one.