feat: enable forwarded ports using built-in proxy (#5673)

* feat: enable ports panel in proxy-uri patch

This makes the forwarded ports panel enabled by default.

* feat: add tunnelProvider in proxy-uri patch

This adds a `tunnelProvider` along with a `tunnelFactory` so that ports
are forwarded and use code-server's built-in proxy.

* fixup!: update import

* fix: skip uri modification if authority host match

This adds a check in our `resolveExternalUri` patch to skip modifying if
the `authority` and the `location.host` match to prevent
`localhost:<port>/proxy/<port>` from being modified.

* fixup!: refresh patch

* fixup!: move authority check up

* fixup!: remove comment

* fixup!: add trailing slash