Add a way to use modelindex always

[rtxa]

It's much better than sending messages overflowing the player, but there are sideeffects like corpses not using the model of the player, this can be fixed inside hl.dll or using a new API.

https://github.com/alliedmodders/amxmodx/blob/27f451a868c3154a0ab0d4d70e0a650074fd485d/modules/cstrike/cstrike/CstrikeNatives.cpp#L861