item_scout: spawn bash buff instead of speed powerup (see also 1791f3d8)

item_scout: spawn bash buff instead of speed powerup (see also 1791f3d8)

prevents a superfluity of speed powerups on some maps (since speed must also spawn for item_haste)

item_scout is often owned by a specific team (supported by buffs, but not powerups)

item_scout is persistent (lasts until death), buffs last longer than powerups by default

In Q3TA: increases movement and firing speed, prevents use of armor
In QL:	caps armor at 50, disables self damage and fall damage and footstep sounds

Why bash? goal of item_scout: to boost hit and run capabilities, to
help with retrieving flags or grabbing important items

Bash helps with this by knocking enemies away instead of having to fight
through them all, and boosting blaster/rocket jumps and crylink running