Explore segmentation of photos on device

[teolemon]

What

• Those 2 MLKit on-device features could be useful for photo addition, allowing to remove background for privacy and noise reduction (other products), and esthetics on the website
• If we want an open solution for F-Droid, we'll need to research it, and see how practical it is.
• https://developers.google.com/ml-kit/vision/subject-segmentation?hl=fr
• https://developers.google.com/ml-kit/vision/object-detection?hl=fr

Part of

• Supercharge the app with artificial intelligence (Tracker) #4027

[teolemon]

@raphael0202 @jeremyarancio FYI