Stateless Validation

# Rationale

Stateless validation would allow for blocks to be validated by network participants running erigon without the need of a comprehensive state database. This capability is a requirement for a platform that I am building.

# Implementation

Do you have ideas regarding the implementation of this feature?

As far I understand erigon already has the capability to generate a block state witness. As such we can introduce a new rpc endpoint of the following format `engine_newStatelessPayload(ExecutionPayload, BlockStateWitness, ChainMetadata)`. The `ExecutionPayload` is the block to be validated, the `BlockStateWitness` is the state witness required to validate the block and the `ChainMetadata` contains required metadata such as previous block hash, chain id and other auxiliary data required for validation. The endpoint would simply return `{status: Valid, ...}` or `{status: Invalid, ..}`.

Are you willing to implement this feature?

Yes I would be willing to implement this feature with support from core devs who can assist in helping me design and specify the implementation.