Update workflows to enable previous major version releases

[oliverschuerch]

Tasks

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1. Update all github action calls, so they run locally (e.g. swisspost/design-system/.github/actions/setup-pnpm@main -> ./.github/actions/setup-pnpm)
2. Add packages/documentation/netlify.config.json -> { siteId: edc7287b-ec63-423c-84aa-c2a1cffbcf87, siteUrl: design-system.post.ch }
3. Update deploy-documentation.yaml workflow to use the netlify.config.json data as input (see example)
4. Add packages/documentation/public/_redirects file.
5. Update new release.yaml from here. Edit the necessary parts:
6. Collect Release Data, old.siteUrl -> design-system-version-${oldMajor}
7. Create & Deploy Netlify Site, --account-slug -> OSS fromSwiss Post
8. Update release-documentation.yaml to use netlify.config.json data