Hearing - Tone down strength of explosion hearing damage

[LinkIsGrim]

When merged this pull request will:

• Title.

This makes a grenade @ 10m equivalent to a ~50 round burst from a .50 BMG static. Manageable with earpro, but still quite loud when closer. Grenades exploding at a player's feet will still blow out their eardrums, but hey, realism.

IMPORTANT

• If the contribution affects the documentation, please include your changes in this pull request so the documentation will appear on the website.
• Development Guidelines are read, understood and applied.
• Title of this PR uses our standard template Component - Add|Fix|Improve|Change|Make|Remove {changes}.

[johnb432]

_shell = createVehicle ["Sh_120mm_HE_Tracer_Red", player modelToWorld [0, 10, 1]];
_shell setVelocity [0, 0, -400];

The above produces a deafness of about 3.4, which is feels way too mild (it's less than a grenade at the same distance). At 5 m, the strength is >20. R_MRAAWS_HE_F produces about 6 at 10 m, so well over 20 when at 5 m.