Is your feature request related to a problem? Please describe.
A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]

monaco-editor: https://github.com/Microsoft/monaco-editor

This is exactly the same task we did for the Output view in Theia: eclipse-theia/theia#7570

• It should improve performance in general as the underlying content is wrapped into a monaco.editor.ITextModel. The logic that handles the UI update would be exactly the same as in VS Code; it's not that bad 😄
• It should align the look and feel all over the application.
• We get copy/paste/find/select-all for the Serial Monitor for free.

Describe the solution you'd like
A clear and concise description of what you want to happen.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.