Convert locale files from ini to json format (#35489)

Migrate from the current INI format to JSON for translations. JSON is
widely supported, including by platforms such as Crowdin and Weblate.

.github/workflows/files-changed.yml

@@ -53,7 +53,7 @@ jobs:
               - "Makefile"
               - ".golangci.yml"
               - ".editorconfig"
-              - "options/locale/locale_en-US.ini"
+              - "options/locale/locale_en-US.json"
 
             frontend:
               - "*.js"