Don't crash on missing translations
Followup of #356 (closed)
Reforis crashes when translation files are missing.
AttributeError: 'NullTranslations' object has no attribute 'json_catalog'
args = ("'NullTranslations' object has no attribute 'json_catalog'",)
with_traceback = <built-in method with_traceback of AttributeError object>
Handle loading of translations so in case that translations are malformed (only babel header and nothing more) or missing, fallback to empty dictionary (no translations).