Improve the Logging and documents

[hackfisher]

system.ExtrinsicFailed should be more explicit, and the error handling strategy should be detailed documented.

{"starter":"","level":"info","message":"finalizedBlockNumber："}
Unknown types found, no types for HeaderInfo,RKT,StakingBalanceT,StakingLedgerT
{"message":"polkadotjs init success!","level":"info"}
{"message":"start BlockChainState","level":"info"}
{"message":"start SubmitToDarwinia","level":"info"}
{"message":"start to get block number info: 7059100","level":"info"}
{"message":"blockInChain: 7439105","level":"info"}
{"message":"Successfully acquired the block number info: 7059100","level":"info"}
{"message":"start build relayHeader extrinsic","level":"info"}
{"message":"Status of transfer: Ready","level":"info"}
{"level":"info"}
{"message":"Successful transfer of with hash 0x3430527275d87245f32ef1c4c9c262c40a2c330300a632c820c6387188ba85fc blockNumber: 7059100","level":"info"}
{"message":"{\"ApplyExtrinsic\":2} : treasury.DepositRing","level":"info"}
{"message":"{\"ApplyExtrinsic\":2} : system.ExtrinsicFailed","level":"info"}
{"message":"start BlockChainState","level":"info"}
{"message":"blockInChain: 7439107","level":"info"}
{"message":"killing","level":"info"}
{"message":"killed...","level":"info"}
{"message":"Logging initialized at debug level","level":"debug"}
{"message":"starting proof server!","level":"info"}
{"starter":"","level":"info","message":"finalizedBlockNumber："}
Unknown types found, no types for HeaderInfo,RKT,StakingBalanceT,StakingLedgerT
{"message":"polkadotjs init success!","level":"info"}
{"message":"start BlockChainState","level":"info"}
{"message":"start SubmitToDarwinia","level":"info"}
{"message":"start to get block number info: 7059101","level":"info"}
{"message":"blockInChain: 7439112","level":"info"}
{"message":"start BlockChainState","level":"info"}
{"message":"killing","level":"info"}

[WoeOm]

pr at #7