Plugins should have protocol-specific metrics

[M0rdecay]

e.g.:

• gRPC server and client (we can use this package as an example - https://github.com/grpc-ecosystem/go-grpc-middleware/tree/main/providers/prometheus)
• HTTP server and client; for server, using middleware, for client, using standard client wrapper, summaryVec in both cases
• kafka consumer and producer; using https://pkg.go.dev/github.com/segmentio/kafka-go#ReaderStats and https://pkg.go.dev/github.com/segmentio/kafka-go#WriterStats