Write indexer backed services

[samlaf]

We use services to read state and events from eigenlayer and avs contracts. We currently only have implementations (eg1, eg2) that read state using eth_ calls and events using websocket subscriptions.

We should write an implementation that is backed by an indexer instead of an eth client.

Action Items

• write a blspubkeycompendiumservice implementation that uses thegraph as backend
• write an avsregistryservice implementation that uses thegraph as backend