VW PQ: Cleanup and prep for upstream (#25351)

* VW MQB: Cleanup and abstractions

* regen CARS.md

* Update selfdrive/car/volkswagen/values.py

Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>

* regen CARS.md

* now that's a refactor of a different sort

* move shifter value init/storage

Co-authored-by: Adeeb Shihadeh <adeebshihadeh@gmail.com>

docs/CARS.md

@@ -231,7 +231,7 @@ A supported vehicle is one that just works when you install a comma device. Ever
 <sup>3</sup>When the Driver Support Unit (DSU) is disconnected, openpilot Adaptive Cruise Control (ACC) will replace stock Adaptive Cruise Control (ACC). <b><i>NOTE: disconnecting the DSU disables Automatic Emergency Braking (AEB).</i></b> <br />
 <sup>4</sup>openpilot operates above 28mph for Camry 4CYL L, 4CYL LE and 4CYL SE which don't have Full-Speed Range Dynamic Radar Cruise Control. <br />
 <sup>5</sup>Not including the China market Kamiq, which is based on the (currently) unsupported PQ34 platform. <br />
-<sup>6</sup>Not including the USA/China market Passat, which is based on the (currently) unsupported PQ35/NMS platform. <br />
+<sup>6</sup>Refers only to the MQB-based European B8 Passat, not the NMS Passat in the USA/China/Mideast markets. <br />
 <sup>7</sup>Model-years 2021 and beyond may have a new camera harness design, which isn't yet available from the comma store. Before ordering, remove the Lane Assist camera cover and check to see if the connector is black (older design) or light brown (newer design). In the interim, if your car has a J533 connector CAN gateway inside the dashboard, choose "VW J533 Development" from the vehicle drop-down for a suitable harness. (Some newer models are also observed to not have a J533 connector.) <br />
 <sup>8</sup>Includes versions with extra rear cargo space (may be called Variant, Estate, SportWagen, Shooting Brake, etc.) <br />