gRPC event bus bridge service

[vietj]

Provide a gRPC service that expose a Vert.x event bus bridge to clients.

• Clients only need to use the bridge proto file
• This client should be usable through the gRPC Web protocol

This service exposes the current bridge interactions we already provide in existing bridges like TCP:

• send service
• publish service
• request/response service
• consumer service (subscribe to an event bus address until the gRPC stream is closed by the client)