Move class-star to a separate repository

[Ambrevar]

I've asked defclass* upstream if they are still maintaing their package and would accept to merge the class* changes.

If not, then I suggest we publish this library, it's too useful to be left inside Nyxt :)
@jmercouris: Shall I move it to @atlas-engineer or to @Ambrevar?

[jmercouris]

I would suggest all libraries we build in the context of Nyxt go to the atlas engineer repository, so that our community contributions are evident

[Ambrevar]

Good news, upstream has accepted most of my patches.
Only one remains dangling: hu-dwim/hu.dwim.defclass-star#3

If it gets merged, then we can switch to the latest version of hu.dwim.deefclass-star.

[Ambrevar]

For now Quicklisp only publishes the stable tag of https://github.com/hu-dwim/hu.dwim.defclass-star, so we need to wait until this gets updated before we can get rid of our class-star library.

[Ambrevar]

Maybe Quicklisp won't update the package anytime soon, so instead I suggest using a submodule for defclass-star.

Then we can remove libraries/class-star and define our own define-class in Nyxt that automatically sets the user class when the class name is exported.

[Ambrevar]

When we do, rename defcondition* to define-condition*.