`svengreb` GitHub account and `@svengreb` npm package scope migration

[svengreb]

With the retirement of the Arctic Ice Studio personal & Nord project brand this project will also move to the real-in-person identity “Sven Greb“ both in the context of the repository to the svengreb GitHub account and the @svengreb npm package scope.
During this migration the currently only npm package @arcticicestudio/remark-preset-lint will be deprecated in favor of the new and upcoming @svengreb/remark-preset-lint that will be published afterwards.

Also the current visual representation of this style guide through the way too outdated and deprecated GitBook major version 2 will be unpublished and removed. The documentations and references will be updated to use the GitHub repository with the Markdown rendering instead for now until a custom website has been implemented using a modern TechStack like Next.js. A simple HTTP redirection page will be published through the gh-pages Git branch that redirects to https://github.com/svengreb/styleguide-markdown to catch possible users and make them aware of the migration.