refactor: cleanup gravity constant handling (#35866)

* refactor: move lateral methods from init to lateral.py (#2594)

* Extracting lateral methods to lateral.py

* cleaning

* more cleaning

* more cleaning

* Making sure it remains where it should

* Leave rate_limit where it belongs

* Moving things to `car/controls/`

* Moving rate limit to get a taste of the changes

* clean

* copy verbatim

* clean up

* more

* now we can format

---------

Co-authored-by: Shane Smiskol <shane@smiskol.com>

* No need to change order of import

* refactor: consolidate ACCELERATION_DUE_TO_GRAVITY import path

* bump opendbc

* update refs

* don't import from opendbc

---------

Co-authored-by: Shane Smiskol <shane@smiskol.com>
Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>

tools/longitudinal_maneuvers/maneuversd.py

@@ -3,7 +3,7 @@ import numpy as np
 from dataclasses import dataclass
 
 from cereal import messaging, car
-from opendbc.car.common.conversions import Conversions as CV
+from opendbc.car.common.constants import CV
 from openpilot.common.realtime import DT_MDL
 from openpilot.common.params import Params
 from openpilot.common.swaglog import cloudlog