Added a parameter in test_body_motion to exclude attached objects from
collision, used to avoid collision with all TileMap tiles with moving
platform motion instead of just the one tile the character touches.
Same changes made in 3D for consistency, and handling potential similar
cases.
-Physics servers test body motion use a class to hold parameters instead
of multiple arguments to make it more readable and flexible since there
are many options
-Improved documentation for test body motion and kinematic collision
-Removed read-only properties for body motion results (not handled in
scripts, so they should be get_ methods only instead)