Setup CI to build the documentation to a Docker image (#208)

* Add Docker deployment

* Remove the manually built version

* Fix the dockerfile

Dockerfile

@@ -0,0 +1,7 @@
+FROM squidfunk/mkdocs-material:latest as build
+WORKDIR /build
+COPY . .
+RUN mkdocs build
+
+FROM docker.io/library/nginx:alpine
+COPY --from=build /build/site/ /usr/share/nginx/html/