Add docs-as-code documentation generation to github actions

[4og]

The publicly accessible documentation should be automatically generated on each PR and when the code is merged to main.

See how it's done in module_template: https://github.com/eclipse-score/module_template/tree/main/.github/workflows

• There is a docs workflow that pushes the documentation to github pages
• There is a docs cleanup workflow
• The homepage: "https://eclipse-score.github.io/docs-as-code", is added to orgs.newRepo('baselibs') in https://github.com/eclipse-score/.eclipsefdn/blob/main/otterdog/eclipse-score.jsonnet

[a-zw]

Waiting for #41 because there is nothing to generate for now.

[4og]

@a-zw, the #41 is done with merging 8a939d2