realize massive ledger data reuse through IPFS

[Ning-Qing]

peers may store ledger files that are up to 90% similar (confirmations of the validity of transactions may be inconsistent), and large amounts of redundant data are a significant cost. When the orderer confirms the block, the block file will be submitted directly to IPFS, and each peer node only records the CID of the block in IPFS (the scheme here may have problems with the validity of the peer confirmation transaction, but the details of this block will not be discussed at present), and when the peer needs to obtain the block file, it can be obtained directly from IPFS through the network.