feat: Background Images for Boxes #316
Description
Is your feature request related to a problem? Please describe.
No, just an unimplemented feature.
Describe the solution you'd like
Introduce the ability to set background images for the boxes, similar to how in-game box customization works. This would allow more cool customization for special boxes. My suggestion is to include some previously used in-game box art and also allow the user to set a custom image.
Additionally, when adding in the box images from in-game, another useful feature would be to read the box backgrounds set in-game from the save files and set the corresponding box images when opening those boxes in OpenHome.
NOTE: This is not a repeat of #288.