[Feature] Query data from a fixed amount of blocks before latest

Description

A nice DevX improvement would be to allow querying for data in a way akin to this

query {
  someEntity(block: {
    number: -100
  }) {
    # fields ...
  }
}

This query would fetch data at block latest - 100.

The rationale here is that a very common use case is to fetch data at a fixed amount of blocks prior to the tip to avoid data inconsistencies due to chain reorgs (or, in other words, to ensure data finality). AFAIK, right now the only way to do that is to first query the latest indexed block, and then perform the desired query at latest - n, which is cumbersome and repetitive.

Are you aware of any blockers that must be resolved before implementing this feature? If so, which? Link to any relevant GitHub issues.

No response

Some information to help us out

• Tick this box if you plan on implementing this feature yourself.
• I have searched the issue tracker to make sure this issue is not a duplicate.

No files or tests are named. Start by tracing the existing GraphQL block argument handling and the mechanism used to obtain the latest indexed block. Confirm how a negative block number should resolve relative to the tip and how reorg finality is handled; done means the example query works without a separate latest-block request and is covered by tests.