Add forwarding API for instance creation functions

[tinchodias]

Pull request #11 only took into account instance-side API, but it would be handy to do it as well for creation. For example:

test02CreateWindow

	| window |
	window :=
		lib
			newWindowTitle: #test02CreateWindow
			w: 800 h: 600 flags: 0.
	self assertEmptySDLError.
	self deny: window isNull.

	self assert: window extent equals: 800 @ 600.

	self waitToSee.

	window destroy.
	self assertEmptySDLError

[tinchodias]

I guess it would become:

test02CreateWindow

	| window |
	window := SDL3Window newTitle: #test02CreateWindow w: 800 h: 600 flags: 0.
	self assertEmptySDLError.
	self deny: window isNull.

	self assert: window extent equals: 800 @ 600.

	self waitToSee.

	window destroy.
	self assertEmptySDLError

[tinchodias]

We may follow a name convention to denote the responsibility of the caller to free the instance, as in Alexandrie: https://github.com/pharo-graphics/Alexandrie/blob/dev/doc/2-CodeConvention.md#ownership-transferred-to-caller

[tinchodias]

This issue is related to #6 as part of the life cycle of objects.