Introduce multi-lingual docs

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

mkdocs.yml

@@ -1,4 +1,5 @@
 site_name: Mobilizon
+site_url: "https://docs.joinmobilizon.org/"
 repo_name: "framasoft/mobilizon"
 repo_url: "https://framagit.org/framasoft/mobilizon"
 extra:
@@ -23,6 +24,9 @@ plugins:
   - git-revision-date-localized
   - minify:
       minify_html: true
+  - exclude:
+      glob:
+        - fr/*
 theme:
   name: "material"
   features:
@@ -37,3 +41,5 @@ theme:
   icon:
     logo: material/calendar
     repo: fontawesome/brands/gitlab
+extra_javascript:
+  - javascripts/redirect.js