Updates to database and API for dropdowns.

data/make-model-import/source-makes.txt

@@ -0,0 +1,53 @@
+acura
+alfa_romeo
+aston_martin
+audi
+bentley
+bmw
+buick
+cadillac
+chevrolet
+chrysler
+dodge
+ferrari
+fiat
+ford
+genesis
+gmc
+honda
+hummer
+hyundai
+infiniti
+isuzu
+jaguar
+jeep
+kia
+lamborghini
+land_rover
+lexus
+lincoln
+lotus
+lucid
+maserati
+mazda
+mclaren
+mercury
+mini
+mitsubishi
+nissan
+oldsmobile
+plymouth
+polestar
+pontiac
+porsche
+ram
+rivian
+rolls_royce
+saab
+scion
+smart
+subaru
+tesla
+toyota
+volkswagen
+volvo