Remove the lisp image and references to it

[danmilon]

See IMG-1954: fully drop the lisp image.

The image is not used at all, so lets sunset it to reduce maintenance cost.

[flovntp]

Hey @danmilon
i think you miss the recent split between single-runtime and Composable image.
This page still reference Lisp (and same on Upsun side).
Could you please also modify the composable-image.md files on both Upsun and P.sh?
https://github.com/platformsh/platformsh-docs/blob/main/sites/platform/src/create-apps/app-reference/composable-image.md?plain=1#L121

I would be happy to contribute to your branch, but it's a fork and i can't :D

ps:

• Upsun preview env
• P.sh preview env

[flovntp]

or maybe i'm wrong and using Composable image, Common Lisp (SBCL) is still supported.
If that's the case, i would gladly approve you PR ;)

[danmilon]

yeah at the moment there's one production use of lisp on the composable image, and it's supposed to be supported. I think it makes sense to keep this one for now.

[flovntp]

Last thing, could you please remove the link in the composable-image.md files (Upsun and P.sh) to the lisp page?

  target does not exist --- create-apps/app-reference/composable-image.html --> /languages/lisp.html

[danmilon]

ah I see. so the composable image pages link to the single-runtime pages? But if we remove the link, it's as if the composable image doesn't support lisp. Anyways, it's OK to undocument it completely then. what do you think?

[flovntp]

Lisp is maintained and supported by the Nix community, so it's supported by us as we supported Composable Image...
But this means we need to keep how to use Lisp in a P.sh/Upsun project.
Maybe we keep the Lisp.md page, and add a banner on top to let the visitor know that if he wants to use Lisp, he would need to use Composable Image.
But that's a complete revamp of the Lisp pages.
invoking @Kemi-Elizabeth here :D

[danmilon]

Yeah nix can support the world, but the list of runtimes is curated by us cause support has to be added for them. The lisp production use I mentioned is internal, so it's probably OK to undocument, and in the meantime the internal thing will be ported to another runtime.