docs: Mkdocs i18n support (#5072)

Signed-off-by: Yifei DIng <yifeiding@protonmail.com>

docs/_klipper3d/fetch-translations.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+# Modify the file structure before running mkdocs
+# This is a make shift script before the current structure of
+# Klipper-translations can be directly utilized by mkdocs
+# Usage: pre-mkdocs.sh <lang_directory_name> <target_lang_name>
+
+#git clone --depth 1 https://github.com/Klipper3d/klipper-translations
+
+while IFS="," read dirname langname langdesc note; do
+  # move and rename markdown files
+  local_dir="klipper-translations/docs/locales/$dirname"
+  echo "Moving $dirname to $langname"
+  for file in "$local_dir"/*.md; do
+    mdfilename="${file/$local_dir\//}"
+    mv "$file" "./docs/${mdfilename//.md/.${langname}.md}"
+  done
+
+  # manually replace index.md if a manual-index.md exist
+  manual_index="./docs/manual-index.$langname.md"
+
+  if [[ -f "$manual_index" ]];then
+    mv "$manual_index" "./docs/index.${langname}.md"
+    echo "replaced index.${langname}.md with $manual_index"
+  else
+      echo "Manually translated index file for $dirname not found!"
+  fi
+
+  # add to translations.yml
+  echo "      ${langname}: ${langdesc}" >> ./docs/_klipper3d/translations.yml
+done <  <(egrep -v '^ *(#|$)' ./klipper-translations/active_translations | tail -n +2)