Research Subquery and Subsquid as a data indexing service

[amatsonkali]

There's some indexing services/frameworks that we may consider using for query enhancement:

• Parity's Substrate-archive: index chain state into postgreSQL (unmantained)
• Substrate graph: A compact indexer based on Substrate-archive. (very little repoactivity)
• Subquery: Prominent indexing service, the free plan allows for 2 active projects. Getting started
• Subsquid: Growing API framework. Getting started
• Hydra: A substrate query framework inspired by The Graph. Getting started

[AugustoLara]

Assigning this ticket to @sebastianmontero only so you can re-assign it to @tlacloc or @didiermis