[sdl3-image] Add new port sdl3-image

[shybovycha]

Add SDL3-image port. There already is an SDL3 port, but none for the relevant components (mixer, ttf, image). Used the latest 3.x release tag (preview-3.1.0)

• Changes comply with the maintainer guide.
• The name of the port matches an existing name for this component on https://repology.org/ if possible, and/or is strongly associated with that component on search engines.
• Optional dependencies are resolved in exactly one way. For example, if the component is built with CMake, all find_package calls are REQUIRED, are satisfied by vcpkg.json's declared dependencies, or disabled with CMAKE_DISABLE_FIND_PACKAGE_Xxx.
• The versioning scheme in vcpkg.json matches what upstream says.
• The license declaration in vcpkg.json matches what upstream says.
• The installed as the "copyright" file matches what upstream says.
• The source code of the component installed comes from an authoritative source.
• The generated "usage text" is accurate. See adding-usage for context.
• The version database is fixed by rerunning ./vcpkg x-add-version --all and committing the result.
• Only one version is in the new port's versions file.
• Only one version is added to each modified port's versions file.

[Mengna-Li]

Note: I will be converting your PR to draft status. When you're ready, please revert to "ready for review". That way, I can be aware that you've responded since you can't modify the tags.

[Mengna-Li]

This is unnecessary, you should remove this and your usage file.

[dg0yt]

Looking at the usage file, I think that it is useful, but it needs to be redacted.

[dg0yt]

Looking at the usage file, I think that it is useful, but it needs to be redacted.

[dg0yt]

I guess that reasonable usage would be like this:

Suggested change

	# this is heuristically generated, and may not be correct
	find_package(SDL3_image CONFIG REQUIRED)
	target_link_libraries(main PRIVATE CMath::CMath SDL3_image::SDL3_image-shared)
	find_package(SDL3_image CONFIG REQUIRED)
	target_link_libraries(main PRIVATE $<IF:$<TARGET_EXISTS:SDL3_image::SDL3_image-shared>,SDL3_image::SDL3_image-shared,???????>)

... with the appropriate target name for static builds in place of ????????.

[dg0yt]

Lacking a line break at the end.