clean up old docs generation in CLI repo

[dangrondahl]

The CLI repo currently contains tooling to generate the old docs site.
Once migrated to Mintlify this can be removed.

Tasks

• Identify all docs generation scripts, workflows, and dependencies in
  `kosli-dev/cli`
• Confirm the new `update-cli-docs.yml` workflow covers all generated content
• Remove old docs generation code and workflows
• Open a PR in `kosli-dev/cli`