Persist state to PostgreSQL

[fracek]

Is your feature request related to a problem? Please describe.

Users that want to sync onchain data to PostgreSQL may want to use the same database to persist the indexer's state.

Describe the solution you'd like

We should add a --persist-to-postgres option to persist data to a specific PostgreSQL database. On start, this persistence should check if the database contains the indexers table and create it if not.

[VenkatTeja]

+1