When the core references `vscode`, we only want to import the types and never generate a real import (which will fail to load). Use `import type` to better enforce this

Const provides better type guards and can make logic clearer

We compile using the alwaysStrict flag so these directives are not needed

This part removes most `use strict` directives that are right after the file header

This reverts commit 27256832 which turns out did not break the import of vs/nls

This reverts commit 7de696a2.

Seems to have broken loading vs/nls in at least one case in insiders

Don't use this import form in places where it is not needed. This prevents us from correctly detecting duplicate imports

Add a mechanism to be a customer of the extension host (share lifecycle) and begin reducing usage of IThreadService

correct localise call, fallback to err if no err.message is available, protected message service against invalid items, fixes #5891