[feature-request][grpc] Make the `daemon.port` optional

[kittaakos]

It would be great if the gRPC server for the CLI daemon could start on any available port if the daemon.port is not defined in the CLI configuration. So when the following is not specified:

daemon:
  port: "50051"

The gRPC server would start on a random port, the new IDE could read the port from the stdout, and could connect to it.

arduino-cli/cli/daemon/daemon.go

Line 124 in a4ee670

logrus.Infof("Daemon is now listening on 127.0.0.1:%s...", port)

Downstream request: arduino/arduino-ide#201

Thank you!

[per1234]

@silvanocerza @fstasi do you think there is any need for the requested capability now that it is possible (#1585) to take the port 0 approach, as done in arduino/arduino-ide#673?

[silvanocerza]

Yes, this can be closed.
If the user wants a random port she can either set the daemon.port config to 0 or use the --port flag.

[fstasi]

@per1234 I confirm we can close this one