[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

Beginne mit den CLI-Einstiegspunkten für tns run und tns debug und konzentriere dich auf deren Lebenszyklus im Watch-Modus und die Verarbeitung von Terminaleingaben. Lege fest, wie angehaltenes Watching, fortgesetztes Watching und manuelles Deployment miteinander interagieren sollen, und überprüfe anschließend, dass die angeforderten Befehle s, r und d funktionieren, ohne den laufenden Befehl zu stoppen.