Remove infinite inertia and ray shapes from CharacterBody

Infinite inertia:
Not needed anymore, since it's now possible to set one-directional
collision layers in order for characters to ignore rigid bodies, while
rigid bodies still collide with characters.

Ray shapes:
They were introduced as a work around to allow constant speed on slopes,
which is now possible with the new property in CharacterBody instead.

editor/plugins/collision_shape_2d_editor_plugin.h

@@ -47,7 +47,6 @@ class CollisionShape2DEditor : public Control {
 		CONCAVE_POLYGON_SHAPE,
 		CONVEX_POLYGON_SHAPE,
 		LINE_SHAPE,
-		RAY_SHAPE,
 		RECTANGLE_SHAPE,
 		SEGMENT_SHAPE
 	};