Proof: manage new consumption-related fields (Receipt upload form, Proof display)

[raphodn]

Story

Following new "consumption-related" fields added to the backend : openfoodfacts/open-prices#387 & openfoodfacts/open-prices#499
--> manage them in the frontend

Todo

• Proof add & edit form (receipt): optional input for receipt_price_count & receipt_price_total : feat(Proof add): add new consumption-related fields to the form #976
• Price add form (receipt proof): optional input for receipt_quantity (default to 1)
• Proof card: show these stats if owner : feat(Proof card): show new consumption-related fields in the footer #977
• Already added prices card: show these stats if filled: Price addition: display current number of prices already inputted #1071

[raphodn]

some ideas on how the "Price quantity" field input could look like