feat: latest vault earn indexer

[btcookies]

Background

Similar to the claimable balances indexer, have a lambda that runs every hour (up for discussion) and pulls latest earns using etherscan api. Similar code is written in python to pull latest harvests from vaults here that can be adapted to ethers and used in program.

One consideration will be structure for storing multiple chain's vaults. One table should be ok, maybe column for chain?

Requirements

• Latest earn timestamps are stored in dynamodb for every production vault in registry
• Earn indexer lambda running on cron

Tasks

• Cron lambda indexing latest vault earns from keeper acl
• serverless infra set up for new dynamo table and schema