Minor Animation Updates for Older Mobs

With new mobs such as the Warden and the Sniffer using keyframe animations, it would be a good idea to update the animations of some older mobs, such as the Villagers, that would benefit from more expressive animations. Some minor tweaks, such as the Zombies tilting their heads a little and having a bit of a limp to their walk would add a lot more to their character, instead of them just walking like any other perfectly-alive mob would. Same thing goes for the Zombified Piglins, which would help differentiate them from normal Piglins. Most of the older mobs don't need an overhaul though, and just some minor tweaks would be enough to blur the lines further between the old and the new.