Make all wall weapons fullbright to fix visibility issues. Properly
precache W_BOWIE assets. Use grenade_bag.mdl instead of grenade world
model when using the grenade weapon.
This rebrands the two under the "HANDHELD" name. The two platforms now
function identically in regards to server functions, making them
unified in behavior and general server-reliant functions.
Adds some utility functions to make grabbing specific pieces of weapon
information in any of a player's slots easier. Fixes some mulekick bugs
as a side effect. Fixes https://github.com/nzp-team/nzportable/issues/52.
