I229 reserved peers deadlock

[SurfingNerd]

#229 - reserved peers management during key gen phase can lead to deadlocks

• refactored peers management and peer transaction to be executed on an additional IOChannel with 1 worker thread.
  Therefore FIFO guarantees are still met.
• removed client lock in the HBBFT Core

Updates to transact_silently:

• Updated the transact_silently method in BlockChainClient and its implementations to return the transaction hash (H256) instead of () upon success. This improves the visibility of transaction outcomes. (crates/ethcore/src/client/traits.rs, crates/ethcore/src/client/client.rs, crates/ethcore/src/client/test_client.rs) [1] [2] [3]

IoService initialization improvements:

• Added a thread pool size parameter to IoService::start calls in ClientService, AuthorityRound, and HoneyBadgerBFT to improve configurability and performance. (crates/ethcore/service/src/service.rs, crates/ethcore/src/engines/authority_round/mod.rs, crates/ethcore/src/engines/hbbft/hbbft_engine.rs) [1] [2] [3]

Honey Badger BFT (HBBFT) engine refactoring:

• Introduced a new IoService for managing peer connections (hbbft_peers_service) and registered a corresponding handler (HbbftPeersHandler). (crates/ethcore/src/engines/hbbft/hbbft_engine.rs) [1] [2]
• Removed unused fields and methods, such as has_sent_availability_tx, peers_management, and related logic for handling availability announcements and internet address announcements. This simplifies the engine's responsibilities. (crates/ethcore/src/engines/hbbft/hbbft_engine.rs) [1] [2] [3]
• Refactored the do_validator_engine_actions method to return a more specific Error type instead of a generic String. (crates/ethcore/src/engines/hbbft/hbbft_engine.rs)

Logging and minor adjustments:

• Improved log messages in the set_validator_internet_address and send_tx_announce_availability functions for better clarity and debugging. (crates/ethcore/src/engines/hbbft/contracts/validator_set.rs) [1] [2]
• Removed redundant code for nonce handling in send_tx_announce_availability. (crates/ethcore/src/engines/hbbft/contracts/validator_set.rs)

These changes collectively aim to enhance the maintainability, performance, and clarity of the codebase.