Add Flight JDBC Connection String example

I have tried to connect using the [JDBC driver](https://arrow.apache.org/docs/java/flight_sql_jdbc_driver.html) added to my Intellij IDEA, with a different combinations of parameters. The driver failed with:

`org.apache.arrow.driver.jdbc.shaded.org.flight.FlightRuntimeException: UNAVAILABLE io Exception`

Any help would be highly appreciated

查看链接的 Flight SQL JDBC driver 文档和现有 issue 讨论，然后使用报告中的参数组合在 IntelliJ IDEA 中重现连接尝试。当 repository 中包含一个清晰的 Flight JDBC 连接字符串示例，并且该示例能够说明所报告的配置和失败情况时，即视为完成。

由索引模型根据 Issue 内容生成。