Design system missing APIs

• Implement activeTheme and activeThemeId APIs.
• An activeTheme change should trigger model update in the current and the host model. The current model might have a binding to model whose activeTheme is changed.
• Verify the changed binding. Return false on invalid binding. Return true on valid binding.
  • The new binding should be a valid DS binding
  • Check for binding cycles.

---- * Automatic loading of the model when design system view is opened

• Automatic saving when model changes (timer compression in model) and/or project is closed
• Provide unused default name for creating a new collection popup TextField to avoid collision
• Update existing bindings when collection is renamed or removed
• Can't create a variable when there is no mode, need a property that shows me there is no mode to block the button
• Setting a binding on itself (binding loop) will crash QtDS
• On calling load/refresh we get the following output std::optional("Error loading collection Module. File \"/home/hag/UntitledProject45/Generated/DesignSystem/Generated.DesignSystem\" does not exist.")