Enhance gRPC error handling and normalize driver results in service handlers

- Introduced truncate_grpc_details function to cap gRPC error messages.
- Updated safe_and_metered_rpc_method to use truncated error details.
- Normalized driver results in configure_rules and deconfigure_rules functions.
- Added checks for devices not managed by any controller in service handlers.
- Created a new YANG model for Huawei NCE application-flow API.