[Feature] Make CLI handle updating webpack configs

Is your feature request related to a problem? Please describe.
When I upgraded to a new version of dev-Webpack; I almost missed the message about
using "./node_modules/.bin/update-ns-webpack --configs" to update my config file... It scrolled right off the screen.

Describe the solution you'd like
tns webpack clean which would reset the config files...

possibly in addition: tns webpack update which would install @latest of the dev-webpack

Describe alternatives you've considered
None, the idea is to make the cli handle it... 😀

Additional context
Shouldn't have to deal with other tool; the CLI should handle it...

首先定位 tns webpack 的 CLI 处理逻辑以及现有的 update-ns-webpack --configs 工作流。确定 clean 是否应重置配置文件，以及 update 是否应安装最新的 dev-webpack；当受支持的 CLI 命令替代独立工具，同时保留预期的配置更新行为时，即表示完成。