Add a way to save to storage the images uploaded to Nutrify

[mrdbourke]

Every image uploaded to Nutrify should be saved to storage (as long as the image is detected as being food).

The image should be uploaded -> passed through food/not_food model -> saved to storage if the image if of food, then track:

• Image UUID - use this to track information regarding different images across the database
• Timestamp
• Pred for image class