Fix Dockerfile and mkdocs for deployment on docker

Dockerfile

@@ -1,4 +1,4 @@
 FROM squidfunk/mkdocs-material
 RUN pip install mkdocs-git-revision-date-plugin
-COPY docs/ .
+COPY docs/ /docs/docs
 COPY mkdocs.yml .

mkdocs.yml

@@ -2,6 +2,7 @@ site_name: F-Docs
 theme:
     name: 'material'
 repo_url: https://git.r4o.ch/francesco/mkdocs/
+docs_dir: 'docs'
 
 plugins:
  - git-revision-date