Implement product data API

A few people have asked for an API to pull data from auscost. I would like to copy the integration schema used by https://github.com/badlogic/heissepreise E.G.: ``` [ { "store": "billa", "id": "00-650902", "name": "\tVivoy bei Blasenschwäche Schwarze Pants für Frauen L", "description": "Unsere diskreten Pants bieten durch das textilähnliche und weiche Material ein angenehmes Tragegefühl. Mehrere Lagen absorbieren Flüssigkeit zuverlässig und verhindern die Bildung von Gerüchen bis zu 12h. <li>Geeignet für starke Blasenschwäche<li>Mehrere Saugkanäle schließen Feuchtigkeit sicher im Saugkern ein<li>Seitliche Schutzbünchen ermöglichen maximalen Schutz<li>Dermatologisch getestet und extra weiche Oberschicht <li>Umfang Größe L: 110-140 cm<li>Farbe: Schwarz</li>", "price": 6.49, "priceHistory": [ { "date": "2024-01-04", "price": 6.49 }, { "date": "2023-04-06", "price": 8.99 }, { "date": "2023-01-24", "price": 10.99 } ], "isWeighted": false, "unit": "stk", "quantity": 10, "bio": false, "url": "vivoy-bei-blasenschwaeche-schwarze-pants-fuer-frauen-l-00650902", "category": "71", "unavailable": true }, { "store": "billa", "id": "00-580756", "name": "'Pfanni' Erdäpfel speckig aus Österreich", "description": "Klasse I", "price": 3.99, "priceHistory": [ { "date": "2023-05-23", "price": 3.99 }, { "date": "2022-04-01", "price": 2.99 } ], "isWeighted": false, "unit": "g", "quantity": 2000, "bio": false, "category": "01", "unavailable": true } ] ``` Not all of this data is available or relevant from both coles and woolworths, but this general structure seems solid. The priceHistory field might be tricky, as the data flow from the application container to the timeseries DB is currently one-way. Returning an empty list would probably be OK for the first pass.