Implement nikola static site generator orgmode compiler
### Problem to solve
Enable possibility to build static site with Nikola using emacs org-mode source files
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### Intended users
Bloggers using emacs and Nikola static site generator
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### Further details
The Gitlab CI/CD already partly [supports the Nikola static site generator](https://gitlab.com/pages/nikola). However Nikola supports using emacs org-mode source files by simply [installing a plugin](https://plugins.getnikola.com/v8/orgmode/). Point 3 in the [troubleshooting section](https://gitlab.com/pages/nikola#troubleshooting) for using Nikola suggests that we simply install the plugin by adding the `nikola plugin -i orgmode` command to the script section in the `.gitlab-ci.yml` file. Although this indeed installs the plugin, the process fails with the message that it needs emacs and org-mode to be installed as shown in the following image:

Of course it would be great if gitlab would support the amazing efficient Nikola + org-mode workflow.
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### Proposal
Add emacs and org-mode to the [`registry.gitlab.com/paddy-hack/nikola docker image`](https://gitlab.com/pages/nikola#building-locally).
Alternatively, the user can build the site locally on his computer but then it would be nice if there is an option to publish the site without using the Gitlab CI/CD pipeline.
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### Permissions and Security
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### Documentation
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### Testing
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### What does success look like, and how can we measure that?
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### What is the type of buyer?
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### Links / references
issue