debt - invoke resolve notebook when opening a notebook in an editor, not when loading a notebook from source

chore - tweak onDidAddNotebookDocument, onDidRemoveNotebookDocument event, use ResourceMap and fix confusion between models and editors

cleanup notebook argument processor, remove INotebookTextModel#handle and use uri instead, https://github.com/microsoft/vscode/issues/105735

replace ICellInsertEdit, ICellDeleteEdit with ICellReplaceEdit, https://github.com/microsoft/vscode/issues/105283

Fix #105195

This removes the initial notebook renderer API and keeps the 'pure'
renderer API described in #102644 and hacked-in previously.

Remaining work in this area, in no particular order:

- Add messaging context to postMessage as requested by Don (API proposal TBA)
- Cleanups around how state is managed internally in the backLayerWebView
- Deprecate the renderer `viewType` in favor of calling it the `id` or `rendererId`

Q: I kept around some of the "transform" functions since the mime type
picking happens there, not sure if there's a better place for this
to happen now, or whether these methods should simply be renamed.