Add Copy Cell Output button or context menu in .NET Interactive

[doggy8088]

Due to this reply from dotnet/interactive#862 issue. I just realized that this suggestion have to report to vscode repo. I would like to suggest two options for the .NET Interactive extension:

1. Add a Copy Cell Outputs button in the context menu when right-click on the cell output

   

2. Add a Copy button on the top-right corner just like GitHub's code fence did.

   

[DonJayamanne]

I vote for the ability to have some sort of a concept of commands in Output items.
This way we can have commands to:

• Copy output item (generic for text & images)
• Save output item (done in Jupyter for images, Enable plot viewer in Native Notebooks vscode-jupyter#6640 (comment))
• Open output item in plot viewer (done in Jupyter for Plots, Enable plot viewer in Native Notebooks vscode-jupyter#6640 (comment))

I have a personal extension that opens vega & plotly plots in an editor (not just a viewer).

E.g. expose the mime type as a context key (so extension authors can have commands show up for some mime types & not others).

@rebornix /cc

[amunger]

this was implemented