Create shareable VSCode settings

[jhnns]

Apparently it's not possible to share VSCode settings microsoft/vscode#15909 (at least for now).

However, I think Copilot's suggestion could be a good workaround. The idea is that this package provides a common vscode settings.json. In your project, you would have an optional settings.local.json with your project-specific overrides. Upon npm install (or as a separate command), it would merge both JSONs into a single settings.json.