[MERGED PR] Mobs entering chutes: Adds actionbar and animation

[vampirate]

I still think this should be limited to people wearing secHUD. There's a good use for it for them, but for people injured and escaping an antag in a very 2d enviroment where your enemy has 360 vision, the chute is one of the few ways you might make a surprise escape. I feel like a ton of us have probably had some amazing feeling moments where we escaped just barely thanks to it.

I think letting everyone have this is going to be a subtle tip away from fun that is gonna kill the potential for those moments.