CANParser: auto-detect frequency

[adeebshihadeh]

Our frequency checks are currently relatively lax. While it would be nice (in theory) to make them stricter, I can't recall an issue the extra strictness would have caught.

And this lets us ship a significant red diff (#2521) to car ports.

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A sample from running test_models on this branch:

0x444 TRACK_14 got 21.00Hz, old 500.00 new 476.20
0x445 TRACK_15 got 21.00Hz, old 500.00 new 476.20
0x156 STEERING_SENSORS got 100.00Hz, old 100.00 new 100.00
0x1A4 VSA_STATUS got 50.99Hz, old 200.00 new 196.10
0x1B0 STANDSTILL got 50.99Hz, old 200.00 new 196.10
0x158 ENGINE_DATA got 100.00Hz, old 100.00 new 100.00
0x17C POWERTRAIN_DATA got 100.00Hz, old 100.00 new 100.00
0x188 GEARBOX_AUTO got 100.00Hz, old 200.00 new 100.00
0x1D0 WHEEL_SPEEDS got 50.99Hz, old 200.00 new 196.10
0x18F STEER_STATUS got 100.00Hz, old 100.00 new 100.00
0x194 STEERING_CONTROL got 100.00Hz, old 100.00 new 100.00
0x1FA BRAKE_COMMAND got 50.99Hz, old 200.00 new 196.10
0x1A6 SCM_BUTTONS got 50.99Hz, old 400.00 new 196.10
0x324 CRUISE got 11.00Hz, old 1000.00 new 909.15
0x294 SCM_FEEDBACK got 25.74Hz, old 1000.00 new 388.50
0x30C ACC_HUD got 11.00Hz, old 1000.00 new 909.21
0x33D LKAS_HUD got 11.00Hz, old 1000.00 new 909.21
0x305 SEATBELT_STATUS got 11.00Hz, old 1000.00 new 909.21
0x309 CAR_SPEED got 10.89Hz, old 1000.00 new 918.22