refactor!: rename media-url file and related parameters (#1651)

- Changed variable `img_cdn` to `cdn` in site configuration file.
- Changed the variable defining the relative path of the image in the post from `img_url` to `media_subpath`

tools/init

@@ -93,7 +93,7 @@ init_files() {
     mv ./${ACTIONS_WORKFLOW}.hook .github/workflows/${ACTIONS_WORKFLOW}
 
     ## Cleanup image settings in site config
-    _sedi "s/^img_cdn:.*/img_cdn:/;s/^avatar:.*/avatar:/" _config.yml
+    _sedi "s/^cdn:.*/cdn:/;s/^avatar:.*/avatar:/" _config.yml
   fi
 
   # remove the other files

tools/release

@@ -156,7 +156,7 @@ build_gem() {
   git checkout "$PROD_BRANCH"
 
   # Remove unnecessary theme settings
-  sed -i "s/^img_cdn:.*/img_cdn:/;s/^avatar:.*/avatar:/" _config.yml
+  sed -i "s/^cdn:.*/cdn:/;s/^avatar:.*/avatar:/" _config.yml
   rm -f ./*.gem
 
   npm run build