integrate eth wallet for chamber validator

[qizhou]

• use Ethereum wallet system to sign and verify validator (and remove existing valKey)
• initialize TM when starting mining. This prevents early and double initialization since miner/worker will immediately send msg to startCh when created.
• remove empty API service (replaced by empty array). The original code blocks the initialization steps of the node and results in unsafe shutdown.
• add a bootnode (will be changed) so that P2P server can start (instead of being blocked)

[blockchaindevsh]

LGTM