Use custom gRPC implementation with Helidon

[a-saksena]

As a Block Node developer
I want to replace Helidon's OOTB gRPC layer with our custom PBJ implementation
So that, I have greater control of the gRPC layer

### Tasks
- [x] Replace `server` subproject `grpc.io` gradle dependencies with PBJ's Helidon plugin
- [x] Remove protoc/PBJ Translator code
- [x] Re-implement `grpc.io` integration to align with the Helidon plugin types, etc
- [x] Test our 3 gRPC method types: Unary, Server Streaming, Bidirectional
- [x] Repair Block Node unit tests
- [x] Fix simulator to work with protoc types and remove PBJ types

[mattp-swirldslabs]

Created PBJ bug ticket to document an issue with Server Streaming integration where the PBJ framework immediately disconnects a client after they connect to receive a stream of block items.

[mattp-swirldslabs]

Created PBJ feature ticket to document framework gaps when clients cancel or close connections to the Block Node.