buid and deploy via CI

xref #7 where @markdoerr said:

Consider generating the static html pages by the CI/CD pipeline (I think we discussed that a longer time ago): So you might utilise the CI machinary to generate the static pages. You can stick with nikola - of even move to the python doc standard sphinx, like we do here: https://gitlab.com/SiLA2/sila_python/-/blob/master/.gitlab-ci.yml which results in static html pages of gitlab: https://sila2.gitlab.io/sila_python/ It might make changes much easier, dynamic and future proof since every commit in master will automatically generate everything without human intervention.