Implement a splash screen

[Doralitze]

After program start the user should be greeted with a quick start like menu. It needs to provide the following options:

• Display recent opened Projects (displaying their notes) and allows the user to quickly load them
• Start a new show file in the patching window
• Start a new show file in the quick console
• Later: import projects (for example from QLC+ or possibly others)
• Later: Start a project from templates (for example one might provide a patching + corresponding output filters for a fixed installation)