Adds one or more transparent web views over the OSX desktop.

• Replace url as key for overlays by uuid
• Allow removing of overlays
• Allow (re)ordering of windows
• Actually destroy web view when unticking in menu (? Maybe just deactivate it?)
• Do not store web view in overlay
• Add (optional) auto disable timer to windows, e.g. for one-shot animations
• Add (optional) midi command for disable/enable
• Cleanup menu update logic
• Detangle webview/menu/overlay state sync handling
• Hide webview while loading, and disable progressive load

• Add window to allow adding/editing URLs
• Added UUID to overlays
• Allow editing of overlay startup state
• Serialize overlay visibility, and use on next startup
• Set tick mark in menu based on enabled state
• Display UUID in config window (read only)
• Improved overlay config window
• Allow enable/disable via MIDI command
• Add option to reload on enable