GM: Tahoe/Yukon 2019 Support

[garrettpall]

Checklist

• added entry to CAR in selfdrive/car/*/values.py and ran selfdrive/car/docs.py to generate new docs
• test route added to routes.py
• route with openpilot:
• route with stock system:
• car harness used (if comma doesn't sell it, put N/A): GM Bolt/Camera Harness

[github-actions]

Thanks for contributing to openpilot! In order for us to review your PR as quickly as possible, check the following:

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  • the goal is clearly stated in the description
  • all the tests are passing
  • the change is something we merge
  • include a route or your device' dongle ID if relevant

[garrettpall]

Closing because I can't get tester to upload a route and due to Comma's lack of interest into porting new GM cars at this time.