Feature - Customise App Icon

[mrspence]

To expand on our existing app icon selection, users could create their own App Icon where they can choose a colour for the Bird and the background.

• Possible?
• UI

[RONAK-AI647]

This issue's solution PR will be in two parts 👍

1. For the Bird icon (color customization)
2. For the UI (color + graphics, or theme modes like dark / fancy / bright???)