Bring your own ReadLine

[dkattan]

The Problem

I am unable to create a web based script editor with a terminal because both PSReadline and LegacyReadLine ultimately call Console.GetKey and Console.Write, causing the input and output to be mapped to the calling process’s Console.

Suggested Fix

Add a -UseUnderlyingHostReadline switch and change the following code:

**

PowerShellEditorServices/src/PowerShellEditorServices/Services/PowerShell/Host/EditorServicesConsolePSHostUserInterface.cs

Line 86 in bd34695

public override string ReadLine() => _readLineProvider.ReadLine.ReadLine(CancellationToken.None);

**

To call _underlyingHostUI.ReadLine() if -UseUnderlyingHostReadline is specified

[andyleejordan]

Linking PR #1748