Add `console` command to open live REPL on running NativeScript application

Is your feature request related to a problem? Please describe.

A REPL is a developer's best friend. Sometimes you just want to play with the native JavaScript integration, or do a quick debug session without all the rigamarole of starting up a devtools session. There's nothing quite like it in terms of exploration.

Describe the solution you'd like

Add a console command that fires up a remote node REPL session to Read expressions from the local machine, Evaluate them on the device, and Print them on the local machine.

Build the app, load it onto a device, and startup a new REPL:

$ tns console ios
{N}> UIButton
[Function: UIButton]
{N}> 

or attach to an existing process:

$ tns console android --device UUID
{N}> android.widget.Button
[Function: Button]
{N}> android.widget.Button

Describe alternatives you've considered
You can use the chrome devtools coupled with the the tns debug command. It just doesn't feel as breezy.

Additional context
Node comes with repl tools out of the box that give you pretty fine grained control over where evaluation happens, how completion and history are achieved, etc....

The only thing would be to implement the remote connection to the nativescript app.

Node の REPL ツールと、issue で説明されている既存の tns debug コマンドから始めます。tns console ios と tns console android --device UUID のエントリポイントを定義し、アプリケーションの起動とアタッチの両方に対応します。ローカルで入力した式がデバイス上で評価され、その結果がローカルの REPL に出力されれば完了です。