Rework airbags (WIP) and improve heat shield textures

For #61 and #85.

Author: Robin Chang

GameData/SDHI/Service Module System/Parts/SDHI_2.5_Heatshield/SDHI_2.5_Heatshield_bump_NRM.dds

@@ -59,4 +59,6 @@ PART
 		amount = 800
 		maxAmount = 800
 	}
+	
+	// Note: airbag animation name is SDHI_heatshield_airbag_inflate
 }