move selfdrive/car to opendbc

[sshane]

WIP

opendbc PR: https://github.com/commaai/opendbc/pull/1049

Open questions

• [ ] where do torque tuning values go?
• [ ] some selfdrive tests import from outside selfdrive
• [ ] panda safety constants require panda submodule
• [ ] test_models should live in openpilot? it compares car state + controls state events against panda
  • A: yes, events will be removed from card
• [ ] perhaps panda safety also lives in openpilot which leaves opendbc/opencar to purely handle the car state
• [ ] come up with struct that holds the car state data. dataclass? capnp?
• [ ] Q: openpilot-specific and car-specific behavior is defined in the car interfaces via events
  • A: use feature flags and openpilot handles the behavior differences. doesn't mention brands. for eg.: enabling on rising edge of resume button or not

[haraschax]

Torque tuning values ideally should go into selfdrive. Does not need to happen from the start.