VSCODE-177: display playground output in editor

[alenakhineika]

Description

• Move playground results from the output channel to the virtual document opened in a split-view mode.
• The results of a playground should have syntax highlighting if they represent a JSON document.
• The results that are not Ja SON document should be printed as plain text with a single color.
• Users can open as many playgrounds they want, but results should be always printed to the same Results editor.
• The Results editor can be drag and dropped to any side of a split-view mode and should keep receiving results from any opened playground.
• The Results file can be saved on a disc and in this case the current Results file stops acting as a Results editor and the new Results editor will be open with the next successful playground execution. It will allow users to freeze some results and compare them with each other.
• Keep printing debug information (eg console.log) in the output channel.

Corresponding issue: #125

Also, this PR includes a small package.json fix to address the following issue: #196

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added

Motivation and Context

• Bugfix
• New feature
• Dependency update
• Misc

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)

[addaleax]

So console.log() etc. go to the output channel now but not the actual result? That seems like a very nice way to separate the two 👍

[alenakhineika]

We were considering different approaches during design sync, but everyone liked this one the most :)