-Allows displaying custom options for specific file format variants
-Added support for scene format import to retrieve custom options
This PR is necessary for #54886 to be implemented properly.
The physics API cannot provide needed functionality to ensure the correct behavior, which might lead to confusion (see `rest_info()`).
However `get_closest_collision_safe/unsafe_fraction()` methods are not removed, because they return correct result from `cast_motion()`.
Reporting rest collision information is needed for move_and_collide and
move_and_slide so floor detection can be done properly, but in the case
of just testing the motion for collision, it makes sense to return false
if the body is able to move all along the path without being stopped.
Updated the logic in test_move and clarified the documentation for
test_move and move_and_collide.
Settings that aren't within a subsection are difficult to reach when
other settings do have a subsection.
This also adds documentation for the project setting.
In all physics servers, body_get_direct_state() now silently returns
nullptr when the body has been already freed or is removed from space,
so the client code can detect this state and invalidate the body rid.
In 2D, there is no change in behavior (just no more errors).
In 3D, the Bullet server returned a valid direct body state when the
body was removed from the physics space, but in this case it didn't
make sense to use the information from the body state.
Center of mass in body's local space is more useful than the transformed
one in some cases, like drawing its position for debug.
It's especially useful to get the generated local center of mass when
in auto mode (by default).
Physics Server BODY_PARAM_CENTER_OF_MASS:
Now always returns the local center of mass, instead of setting a local
center of mass and getting a transformed one.
This causes compatibility breaking, but it makes more sense for the
parameter to be consistent between getter and setter.
Direct Body State:
There are now two properties, because both of them can be useful in
different situations.
center_of_mass: relative position in global coordinates (same as before)
center_of_mass_local: position in local coordinates
