Blockchain node

Privacy engine changes:
- Implemented new privacy protocol which decreases network load and latency;
- gRPC stream of events has been added;
- Optimized interaction with the PostgreSQL;
- The opportunity to upload and download privacy data via gRPC has been implemented;
- Distribution of data has been accelerated due to integration with the NG mechanism.
Smart-contract updates:
- Implemented the circuit breaker pattern for smart contract error handling;
- New gRPC stream with smart contract execution statuses has been added;
- Enhancement of the smart contract error interface: error classes fatal and recoverable have been added.
Performance optimizations:
- The mechanism for distribution and downloading of micro-blocks has been accelerated;
- Support of the parallel execution of smart contracts with the same Docker image has been added;
- The process of smart contract initialization has been divided from execution and is performed beforehand;
- Added support of the updated GOST cryptography.
Implemented the watcher node mode with minimal resource consumption;
Healthcheck reorganization:
- Checks of RocksDB state and free disk space have been added;
- Check of external services has been migrated into the dedicated endpoint.
gRPC improvements:
- Configuration parameters of public services have been moved into the common section;
- Responses including public keys have been enhanced with the address field.
A lot of minor fixes.

Blockchain client

Added integration with WE Wallet extension for Chrome: sign transactions using keys stored in extension;
Added support for ERC20-like token transfers.