Implement new vscode-command : PowerShell.InvokeRegisteredEditorCommand

[kamilkosek]

Changes are very simple , but for now it´s enough to play around 😄
https://github.com/kamilkosek/vscode-powershell/tree/HTMLContentViewPlayground
Test Script
Note: This only works if the content view accepts JavaScript

[daviwil]

Would you like to send the InvokeRegisteredEditorCommand as a PR too? If you can leave the JavaScript enabling commit out then I'll add that part next week :)

[kamilkosek]

Sure, but since I´m new to 'Contributing to public GitHub Repo´s' i need to figure out how to leave that commit out 😆

[kamilkosek]

Maybe we will have someday a convenient way to achieve something like this:

I ❤️ GIF´s

[daviwil]

Love the GIF! Really cool to see everything hooked up end to end. We can definitely look for ways to make it easier to build tool UIs, the PowerShellEditorServices.VSCode module might be a good place for that.

Fixed with PR #919