For #271167
This makes it so our built-in extensions can mostly be built using `tsc` on the command line. Previously the extensions were picking up a lot of typing info from the root `node_modules` that meant they weren't truly independent
* forwarding: add built-in tunnel forwarding extension
- Support public/private ports, which accounts for most of the work in
the CLI. Previously ports were only privat.
- Make the extension built-in. Ported from the remote-containers
extension with some tweaks for privacy and durability.
- This also removes the opt-in flag, by not reimplementing it 😛
Fixes https://github.com/microsoft/vscode/issues/189677
Fixes https://github.com/microsoft/vscode/issues/189678
* fixup! comments
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Co-authored-by: Raymond Zhao <7199958+rzhao271@users.noreply.github.com>
