Refined default values for mouse `sensitivity` (halved from 6 to 3) and master volume (9.0 to 7.0).

Default master volume has been lowered from 9.0 to 7.0 displayed in in-game settings (0.7 to 0.25 cvar value).

I would heavily prefer if some people had to raise the volume to hear properly instead of ear raping others with higher base volume in their audio setups.

Default sensitivity has been halved from 6 to 3.

A lot of modern mice have enough DPI to the point where 6 will be uncontrollable and just spins the player around without any precision.