Entities that are "planted" on bodies of water are floating.
This does away with the "floating" mode.
To mark that entities should by default be floating when placed in
water the boolean property "floats" has been added.
An entity becomes "submerged" when it moves into a body of water.
Currently we only check if its y-position is below 0, but we aim to
provide better support for various water entities in the future.
These properties didn't work out when we moved to a physics based world.
Instead we've introduced the properties "planted-offset" and "planted-scaled-offset".
These properties takes a float and specified vertical offset for planted entities.
Likewise with "planted-rotation" which specifies a rotation applied for planted entities.
"active-rotation" keeps track of any applied rotation.
This property tells how the entity should behave when put into
different modes. Currently we only allow for specific transformations
to occur.
The mode specifications are registed in properties where "mode-" forms
a prefix, and the mode a suffix. For example, "mode-planted".
This also does away with the "plantable" property.
