Update MSF AT Units

[Emythiel]

• Light AT units now use the black MAAWS
• Switched the Viper Light Harness as the backpack
• Updated some NVGs used by DDogs and Pilots/Crew
• Corrected a weapon attachment for regular marksmen

Note: Requires next Theseus Services update which adds the black MAAWS and coyote/green viper backpacks