Remaining kernel webview layer protection

[rebornix]

Re #10152

It includes the remaining work for removing webview dependencies from kernels:

• Move Jupyter Export/Import into webview/extension-side for now, as this component depends on interactive-window and notebooks
• Move Kernel server preload into webview/extension-side for now as it depends on interactive-window, notebooks and kernel.
  • It feels like the kernel server preload should be part of kernels but currently it has assumptions of how a kernel is loaded (in a notebook or iw). We should take a look later if we should move off notebook/iw for this feature.

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR).
• Title summarizes what is changing.
• Has a news entry file (remember to thank yourself!).
• Appropriate comments and documentation strings in the code.
• Has sufficient logging.
• Has telemetry for feature-requests.
• Unit tests & system/integration tests are added/updated.
• Test plan is updated as appropriate.
• package-lock.json has been regenerated by running npm install (if dependencies have changed).

[rchiodo]

Would it make more sense to put this into the interactive src tree? It has nothing to do with webviews but at least it depends upon the IW code.

[rebornix]

Quite a few modules in webview/extension-side actually are not webview related, I guess they are under these folders as the extension used to be separated to extension-side and webview-side. I'm wondering if we can introduce a top folder for these modules/features, not sure what name to use yet, but something like contrib, plugins, integration, etc.

[rebornix]

Would it make more sense to put this into the interactive src tree? It has nothing to do with webviews but at least it depends upon the IW code.

I'll put this in my todo list for the second round of refactoring.