[FEATURE] TNS command for screen recording on-device

Hey Nativescript team,

As always thanks for all the hard work -- using Nativescript Vue and enjoying it immensely!

After being thoroughly impressed by the tns resources splashes generate command, I thought it would be great to have a tns subcommand that started/stopped/extracted screen recordings from a device. It's not hard to do with recent versions of android (adb shell screenrecording /sdcard/whatever.mp4), but it might be even more convenient to use a tns command to do it (and pull out the file afterwards).

(I hope I'm filing this feature request properly -- none of the template instructions seemed to deal with feature requests, it was all about what to put for but reports...)

首先检查现有的 tns resources splashes generate 命令，以及 CLI 如何调用 Android 设备命令。将该流程与 adb shell screenrecording /sdcard/whatever.mp4 进行比较，包括获取生成的文件。完成标准是：一个 tns 子命令可以启动、停止并提取设备上的录制内容。