fix: use url as cache key which contains query params

[alfetopito]

Summary

Now that the caching was fixed on #67, the next issue was exposed.

Unfortunately I only noticed after it was already deployed to prod :(

Right now, the cache is the SAME for all requests.
That's because the cache key used in the request path: req.routerPath which is /proxies/coingecko/* for all requests.

Changed to req.url which does contain the full url path including the search params. E.g.: /proxies/coingecko/simple/token_price/ethereum?contract_addresses=0x6B175474E89094C44Da98b954EedeAC495271d0F&vs_currencies=usd

Testing

1. Start the server locally with yarn start
2. Query one address: curl -X GET http://localhost:3000/proxies/coingecko/simple/token_price/ethereum?contract_addresses=0x6B175474E89094C44Da98b954EedeAC495271d0F&vs_currencies=usd

• Should receive the price for the asset

3. Query the same asset again

• Should receive the same response

4. Query a different asset: curl -X GET http://localhost:3000/proxies/coingecko/simple/token_price/ethereum?contract_addresses=0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2&vs_currencies=usd

• Should have a DIFFERENT price and the token address in the response should match the one in the query

[alfetopito]

Tested on infra with https://app.pulumi.com/cowprotocol/bff/staging/updates/183

All good, proceeding with release. Please post merge review.

[anxolin]

🙈

Thanks