Investigate monaco for input prompt in Python Interactive Window

[rchiodo]

Autocomplete may be easier and look more consistent if we used it.

Questions still open:

• Cursor - it supports line and block.
• Theming - only supports vs and vs dark. Might be able to use this to just set background? The regular editor gets around this by doing its own tokenization and setting a global css that matches the tokens. See https://github.com/Microsoft/monaco-editor/blob/master/test/tokenization.html
• Autocomplete - this is the good part. It will look like VS Code and we won't have to implement the drop down.

[rchiodo]

Might be able to use this too:
https://github.com/brijeshb42/monaco-themes

[rchiodo]

This issue describes how to do custom tokenization
microsoft/monaco-editor#306