Bind Shape2D draw method

[Xrayez]

Sort of closes #6750. The method was not exposed to scripting so it wasn't actually possible to make a plugin to draw shapes out of Shape2D resources. If this is merged, then #16483 can be implemented via GDScript without much hassle.

The gist of drawing with script:

extends Node2D

var shape: Shape2D

func _draw():
	shape.draw(get_canvas_item(), color)

I have also a ShapeCast node proposal which could benefit from this (if done via script): godotengine/godot-proposals#710.

Also note that there's no 3D related drawing methods available for Shape3D (likely uses some other technique for drawing).

Also worth cherry-picking this to 3.2.

[Xrayez]

Documented the method. Note that VisualServer was renamed to RenderingServer, so a reference in the documentation needs to be changed while porting this to 3.2.

[reduz]

This is ok, but do you think you can rename to draw_shape? as draw is a signal and those are now first class on master branch (name will collide with method).

[Xrayez]

@reduz certainly doable, but does that mean Texture's draw method should be renamed accordingly? Note that we're talking about the resources (Shape2D being resource), and not the nodes such as Node2D which does have draw signal, do I understand you correctly?

[reduz]

Ah I See this is for the shape itself, guess its ok then

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.2.2.