Design how an extension looks like as a card in the list

The card shows the following items:

• icon
• display name
• display vendor 
• description (oneliner)
• lifecycle status (see previous item)
• publishing status (production or preview)
• strip downloads number 
• read-only state 

Evaluate whether interactions are feasible (or constrained to details view only) - this can also be postponed to Qt Creator 16, since the interactions shall always be doable in the details-view. 

• interactions explicitly as buttons 
• interactions via context menu (consuming less space)