Iroh CLI better error for connection refused

[faassen]

Currently we get this:

Error: status: Unavailable, message: "error trying to connect: tcp connect error: Connection refused (os error 111)", details: [], metadata: MetadataMap { headers: {} }

Caused by:
    0: transport error
    1: error trying to connect: tcp connect error: Connection refused (os error 111)
    2: tcp connect error: Connection refused (os error 111)
    3: Connection refused (os error 111)

when the right services can't be found. We should give something more friendly.