CI: Remove docs build from pipelines
- [X] closes #29472

At the moment we're building the web and the docs from both Actions and Pipelines. While is still under discussion where things should be hosted, it's probably worth to just build on Actions for now, and publish from there to both the OVH cloud, and to GitHub pages.

**This needs the GitHub pages ssh key to be added to the secrets of this repo with name "github_pages_ssh_key".*** Can someone with permissions please add it? Or if we already got it with a different name, please let me know the name.
