When merged this pull request will:

• Add a config value to set an upper limit on a magazine's loudness, potentially more useful than the existing ammo hearingDamageFactor value for weapons with high firing rates, which reuse ammo types that would otherwise be too quiet on other guns.
• Limit the loudness of RHS gatling guns / aircraft weapons using the new config value. Makes cannons like the Mi-8's UPK-23 (23mm) gun pods and the A-10's GAU-8 more usable, since before they'd cause deafness in just a few seconds of consecutive firing, even while wearing vehicle crew earpro.
• Add Peltor Earpro to the RHSAFRF 6M2 earmuffs' facewear variant, where previously only the headgear variant provided earpro.