elixir-grpc/grpc: An Elixir implementation of gRPC

A comprehensive Elixir implementation of gRPC that supports unary and streaming RPCs, interceptors, HTTP transcoding, and TLS. The library uses a unified stream-based API for all RPC types and includes features like client adapters (Gun/Mint), CORS support, connection backoff, and gRPC reflection. It provides code generation from protobuf files and supports both server and client implementations with composable stream transformations.