Make a VTApiRoutines servicer that does minimal translations instead of
environmental simulation for some output methods. Remaining methods are
backed on the existing console host infrastructure (primarily input
related methods).
## PR Checklist
* [x] I work here
* [x] It's Fix-Hack-Learn quality so it's behind a feature gate so we
can keep refining it. But it's a start!
To turn this on, you will have to be in the Dev or Preview rings
(feature staged). Then add `experimental.connection.passthroughMode:
true` to a profile and on the next launch, the flags will propagate down
through the `ConptyConnection` into the underlying `Openconsole.exe`
startup and tell it to use the passthrough mode instead of the full
simulation mode.
## Validation Steps Performed
- Played with it manually in CMD.exe, it seems to work mostly.
- Played with it manually in Ubuntu WSL, it seems to work.
- Played with it manually in Powershell and it's mostly sad. It'll get
there.
Starts #1173
2c2f4f9be2