Storage proof network

[markspanbroek]

This is a design for an off-chain network for validating storage proofs. Instead of checking each storage proof in a smart contract on-chain, we let the proof network check these proofs. Only when a proof is missing we go on-chain to enact slashing. The main goal of this exercise is to reduce the costs of submitting and validating proofs, which has shown to be a limiting factor for the profitability of storage providers and the scaling of the storage network, even when deploying on a rollup or sidechain.