[Unlinker] Add command to dump every fastfile in the search paths at once

[JezuzLizard]

Currently you have to manually specify the fastfile you want to unlink and only that fastfile will be dumped. However, I'm suggesting a command that just loads every fastfile in the search path sequentially and then dumps each fastfile to disk like the normal unlink functionality. This way a modder could quickly generate a dump of all the assets in a game, and then they'd have a similar level of modding access to raw assets like the official mod tools provide for other CoD games.