Include market cap ranking in tokens list

[onyb]

Add an optional field to TokenInfo model called rank which includes market cap ranking pulled from Coingecko. For tokens sourced from Jupiter, we populate the rank if there's an overlap with the Coingecko list.

Once the ranking is available in our tokens index in Redis, we will list tokens sorted by market cap for an empty query to /api/tokens/v1/search endpoint.