Get market orderbook

curl --request GET \
  --url https://api.context.markets/v2/markets/{id}/orderbook

{
  "marketId": "<string>",
  "bids": [
    {
      "price": 123,
      "size": 123
    }
  ],
  "asks": [
    {
      "price": 123,
      "size": 123
    }
  ],
  "timestamp": "<string>"
}