1.6.0

🎁 Receive, archive and unarchive items

• Add functionality to put items into archive
• Add functionality to get items from archive
• Add functionality to mark items as received
• Add status field to Reservation
• Add archival field to Item
• Extract english texts into language file
• Extend PageContext to hold actions aka links for templates
• Unify page generation in controller
• Improve button design
• Setup Travis CI