ArrowFlight: Support compound paths

Function [arrowFlight()](https://clickhouse.com/docs/sql-reference/table-functions/arrowflight) allows to specify only one-component path to a resource:

```
SELECT * FROM arrowFlight('host:port', 'dataset', 'myuser', 'mypassword');
```

However ArrowFlight itself supports [multi-component paths](https://arrow.apache.org/docs/cpp/api/flight.html#_CPPv4N5arrow6flight16FlightDescriptor4pathE). We need to support them as well:

```
SELECT * FROM arrowFlight('host:port', ('path1', 'path2', ...), 'myuser', 'mypassword');
```

Also if ClickHouse is used as an ArrowFlight server it would be nice to allow handling two-component paths as pair `(database_name, table_name)`. (Currently ClickHouse as ArrowFlight server only allows one-component path which is handled as a table name. Thus it allows reading and writing from the current database only.)