Set weapon position to NextBot center in ENT:PickupWeapon

[Zaurzo]

Fixes https://github.com/Dragoteryx/drgbase/issues/10

The problem was that the weapon is left at worldspawn and parented, so for example, if you spawned the NextBot in a map like gm_flatgrass, you would almost never be able to hear the gun shots

[Dragoteryx]

You're only setting the weapon's position when the nextbot picks up the weapon, wouldn't it be better to set it in the nextbot's serverside Think hook?

[Zaurzo]

You're only setting the weapon's position when the nextbot picks up the weapon, wouldn't it be better to set it in the nextbot's serverside Think hook?

The weapon gets parented to the NextBot, constantly setting the position in Think seems unnecessary