Changes to Monolith Behavior

1. Stopped Monoliths from teleporting players while in Limbo. This was a
serious issue on some modpacks if players got unlucky.
2. Decreased the required Monolith aggro level to start spawning
particles around a target player. The required level was so high,
combined with the current Monolith speed, that players would hardly see
the particles.
3. Disabled Monolith sounds in Limbo. Some of the sounds were really
annoying in Limbo. Usually they only get to play for a moment before a
player is teleported, but since no teleports occur in Limbo and the area
is full of Monoliths, the constant noise is aggravating. It would also
drown out the background music.