Created translations for order page

• Created the translation for the order items page (/order_items) with the yml files from the I18n repo. (en, de, da, es)
• Used the Pluralization for the oders in the system.
• added a translation for the models and their attributes
• Translated the date (created_at)
• Used the Mobility gem to translate the shirt names

@fhs49062 (Michelle Türtscher)