Arrow Flight SQL example JDBC driver incompatibility

[istvan-fodor]

Which issue does this PR close?

Closes #5665
Closes #5669

Rationale for this change

It would be great if the example Flight SQL server would support integration with the Arrow JDBC driver. This would demonstrate the cross-platform nature of Arrow quite well.

This PR changes the example flight_sql_server so we can query it from Java using the Arrow JDBC driver.

What changes are included in this PR?

1. authorization header is returned with contents "Bearer "
2. Added clear_token() to FlightSqlServiceClient to give the client the ability to re-authenticate.
3. The location field returned by get_flight_info_prepared_statement uses a "grpc+tcp://127.0.0.1" as its location. Instead it should include the host and the port.
4. do_action_close_prepared_statement needs to include at least an empty stub (return Ok(())).

Are there any user-facing changes?

No

[Jefffrey]

Makes sense to me 👍

[Jefffrey]

We might have to separate the listening address vs the server address to make things clearer 🤔

Thoughts on this?

[jduo]

We might have to separate the listening address vs the server address to make things clearer 🤔

Thoughts on this?

If you have FlightInfo return an empty location, clients can re-use the connection that was used for the GetFlightInfo request. This is useful for the case where returning this IP/host is non-trivial.

[istvan-fodor]

We might have to separate the listening address vs the server address to make things clearer 🤔
Thoughts on this?

If you have FlightInfo return an empty location, clients can re-use the connection that was used for the GetFlightInfo request. This is useful for the case where returning this IP/host is non-trivial.

I can add this change, and just return an empty list - it seems to me the best default case that makes sense for most users. The FlightEndpoint struct has good comments about this too.

[istvan-fodor]

I went ahead and added the change suggested by @jduo and removed location from the returned FlightEndpoint

[Jefffrey]

Looks good 👍

[Jefffrey]

Suggested change

	let addr_str = "0.0.0.0:50051";
	let addr = addr_str.parse()?;
	let addr = "0.0.0.0:50051".parse()?;
	let svc = FlightServiceServer::new(FlightSqlServiceImpl {});

Minor nit, but we can revert to what it was previously (and down below too)