Track, follow and provide feedback on Sourcify API v2

[wmitsuda]

We currently don't integrate with the Sourcify API directly, but we should on the future, more specifically the API v2 which is on design phase.

Resources:

https://sourcify.stoplight.io/docs/sourcify-apiv2/branches/main/
ethereum/sourcify#1470
ethereum/sourcify#1545

I think we should keep supporting the offline data formats which is very convenient for researchers, but also supporting the API would be better for fresh data.

[sealer3]

I signaled my approval of the v2 API - specifically, the "get verified contract" endpoint which matters for us. Access to the source map and the storage layout will let us do some neat things the other block explorers haven't done yet like #2500 and #2501.