VW MQB: Harness updates

[jyoung8607]

Prep for enabling VW MQB longitudinal in master: swap all harness recommendations to the gateway (J533) harness. I can't currently make openpilot longitudinal work at the camera, because I'm still working on software-disabling the stock radar.

Someday I'll have to make software-disabling work, because the gateways on very new MQB-A0 along with all MQBevo are much harder to build harnesses for. But we don't yet have camera harnesses for those vehicles in the store (though @vanillagorillaa has a production prototype). Gateway integration also lets us preserve stock FCW/AEB.