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

[MarkNstein]

This is "hot" again (as far as I care).

What're your thoughts on:

• Remove all interruptability from the action; thematically treat it as someone making a strong leap-and-tuck into the chute - pretty hard to stop someone's midair motion.
  
• Keep the animation starting as soon as the click-drag is done.
  
• Shorten the animation to 0.2 seconds. My original PR gifs were set to the old delay duration of 0.5 seconds.
  
• Open the chute UI once the animation ends. (Same as current behavior)