[FlightRPC][Java] Provide standard way to get client IP address

[asfimport]

Obtaining the IP address of the client can be accomplished via gRPC, but the gRPC interface exposing this information is considered unstable.  It would be good to expose this through a standard interface in Flight, both to buffer any future changes/instability in gRPC, but also in support of alternative transports.

Reporter: Todd Farmer / @toddfarmer

_{Note: This issue was originally created as ARROW-16565. Please see the migration documentation for further details.}