This commit completely reworks the Root Target ability implementation by
replacing the repeated teleportation code with potion effects.
The old implementation relied on teleporting the target every tick for a
given duration, but because teleporting also involves pitch and yaw, the
result was a constant "snapping back in place" experience.
The new implementation works by applying the following potion effects
with a very large amplification:
- Slowness, to prevent the player from moving out of place.
- Slow falling, to negate fall damage.
- Negative jump boost, to prevent the player from jumping around.
Note that the jump boost uses a _negative_ amplification to make it have
the inverse effect, i.e. a much worse jump ability. It is still possible
to jump an arguably negligible amount away from the root location.
Fixes#490
Makes the class chest armor guessing logic pair `"ELYTRA"` up with the
chest piece slot. This specific matching works, because there are no
underscores in the `"ELYTRA"` item name.
Fixes#616
Nesseley