Implement the not implemented methods in eth_types.nim

[kdeme]

eth_types.nim has a bunch of not implemented methods: https://github.com/status-im/nim-eth/blob/master/eth/common/eth_types.nim#L344

Need to go over the list and see what is necessary & implement them.

getBlockBody and getReceipt are needed for eth_protocol. Others might be needed also for eth rpc.