Have an option for the integrated terminal to behave more like PowerShell ISE.

[ciaccotaco]

Update the integrated terminal to behave like PowerShell ISE

1. In PowerShell ISE, when hitting F8 and executing selected text, that selection is not placed into the Terminal's history. So when you hit up in the command prompt, you run through the history of what has been typed into the terminal. Currently, the VSCode PowerShell Extension combines both the user's inputted terminal commands and the selected text executed through F8.
2. While not as important, it would be nice to have clear / cls / Clear-Host to clear the entire screen, not just what is shown in the window (like how ISE does it).

Thanks!

[TylerLeonhardt]

I have some PR's out to address the Clear-Host behavior since it's highly requested - #2316

As for your first point, that seems like a reasonable feature request.