Lib JPEG improvements

[fjtrujy]

Description

This PR does 2 things:

• Remove the custom libjpeg library created a decade ago, and use the lasted and better supported libjpeg-turbo without any additional change.
• In order to make easier existents homebrew migrations, another library called libjpeg_addons has been created, offering "similar" functionality as the existing one.

I will create additionals PRs in gskit, OPL and wLE

Thanks

[rickgaiser]

Overall a great improvement to switch to using libjpeg-turbo. Thanks!

But the addons library in general I would have preferred not existed. If applications use libjpeg-turbo directly, they have full control over it's capabilities. An "in between" library should not be needed. If added for compatibilty reasons only it's ok.

Perhaps comments can be added to indicate the library is for compatibility only, and the preferred way is to use libjpeg-turbo directly?

[fjtrujy]

Hello @rickgaiser,

I understand all your comments, and they make totally sense, however nowadays every single SDK, also exposes some additional frameworks or tools to make developer life easier.

This is why having these functions in additional libraries, could be good for lazy developers that just look for an easy solution, otherwise, for instance, where you will expose a function to generate a screenshot in a jpg format?
Would remove the function from the ports and include it in every single app.....? I don't think so.

Anyway, I enforce, the idea that both OPL and wLE should use libjgp directly and use their own implementation, but it is up to them.

What do you think?

Thanks

[fjtrujy]

@rickgaiser I will do an improvement in the ps2sdk for the screenshot functions, it is currently so weird, but I will do as a separate PR.

Thanks