add server option for realistic/arcade sound to default to a clientside preference

Whether sound is 'better' in realistic or arcade mode is completely preference / opinion based, and such is heavily influenced by an individuals playstyle, which varies significantly between every player on any single server.

as such, weighing the proportions of both sides (where neither side is a minority) to validate the expense of either group, is not a reasonable approach; as that compromise between either preference is a completely optional problem to have.

By allowing servers to choose between:

- defaulting to user preference, or

- enforcing a specific option,

Both user preferences can be satisfied without expense to the other, and without any expense to servers who choose to maintain a certain enforced option; this change may benefit many to only a few, but it is a disadvantage to nobody, and therefore is a general net positive to all.

the issue to why we wouldn't already have that is probably due to the fact realistic sound can obfuscate distant gunshots and even hits to your own grid, so having players using differing options in the same server could disadvantage players with realistic sound, especially in direct pvp with another using arcade (pve too but is a less directly a disadvantage between players);

However, that aspect would be just fair as before, and at worst one player is minorly disadvantaged; 1: pvp players are more likely to use arcade sound, so differences between players in combat is less likley, uncommon, 2; in the case of a mismatch; the player using realistic sound would have opted into such option anyway, knowingly accepting such disadvantage and should therefore still be satisfied (otherwise they are a silly billy).

I am aware there are other threads and discourse on the topic of official servers switching to realistic sound, but pretty please do not consider this the same, it is a specific qol feature request i'd like to see (that coincidentally happens to solve that problem quite neatly)

(I also believe standard official servers should choose to respect the clientside preference, and only hardcore servers should limit user preference; because how could you play warefare3 but be deaf to the hellfire)