Create sample plugin template for Qt DS

We need a sample git project that is a template plugin. What the plugin should have is

• basic build setup
• open a dockable widget that can receive data from Qt DS
• have basic controls for the plugin window
• document (on the code) 
• enabled branding (look and feel of Qt DS)

For the first phase it's ok to 'need' sources from Qt Creator or Qt DS to compile the plugin. Later on we need to have headers separate.