updates the default time zone for interface results

[binbin0325]

Please do not create a Pull Request without creating an issue first.

What is the purpose of the change

修正config相关接口返回时间时区-8的问题。例如获取配置历史列表查询以及历史配置详情等，接口中返回的(lastModifiedTime)最后修改时间字段比真正操作时间少8小时。

原因：spring转json的默认实现jackson中会根据时区去转换时间，而jackson的默认时区跟国内应该是相差8小时，所以在时间换算上自动减去了8小时。

相关链接：https://my.oschina.net/u/4391021/blog/3580942

Brief changelog

添加spring.jackson.time-zone=Asia/Shanghai 配置

Verifying this change

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[KomachiSion]

Can we get the time zone from the system? Specify it in default conf file may not great.

[binbin0325]

Can we get the time zone from the system? Specify it in default conf file may not great.

I think it's better to get the time zone in the system,I'm going to try to solve it

[KomachiSion]

CI failed due to check style not pass.Please check it.

BTW, can you add some unit test?