[CLI] Manual watching the source changes

From @raffaeler on February 6, 2019 10:58

Is your feature request related to a problem? Please describe.
When tns run is started, it takes a while before deploying the application. For this reason I prefer to run in watch mode (tns run or tns debug).
Anyway, when you are doing more than a trivial change, it would be useful to manually trigger the compilation/deploy without stopping and re-running tns run or tns debug.

Describe the solution you'd like
When the terminal is in tns run or tns debug it can accept keyboard commands. It would be useful to add support for three commands while the terminal is watching:

• 's' key: suspend watching
• 'r' key: resume watching
• 'd' key: deploy while in suspended mode

Describe alternatives you've considered
Stopping and restarting tns run or tns debug is way too slow.

Copied from original issue: NativeScript/NativeScript#6865

從 tns run 和 tns debug 的 CLI 入口開始，著重於它們的 watch 模式生命週期和終端輸入處理。定義暫停 watching、恢復 watching 和手動部署之間應如何互動，然後驗證所要求的 s、r 和 d 命令能夠在不停止正在執行的命令的情況下運作。