Load config from MPT on node starts and update on block finalization

[peterlimg]

To avoid loading config from MPT every time when need to access the config info. Such as the code is called each time when selecting blobbers for blobber challenge generation and get config REST handler. https://github.com/0chain/0chain/blob/f858985cdc34c5ba14378afbe43fc26998c3149e/code/go/0chain.net/smartcontract/storagesc/handler.go#L669-L683

[peterlimg]

https://github.com/0chain/0chain/pull/2090#issuecomment-1423050633