Feature/navigation#110

Created by: wasabideveloper

Implementation of feature #110 (closed), replaces original draft of b73bf4859a0daa89b56138e6567d618c86585e0b (feature/globalNavigation#110). Please close the branch too (without merging).

• ran checks
• ran tests
• ran flake8
• tested views by hand:
  • /
  • /orders
  • /orders/{orderId}
  • /orders/new [get/post]
  • /downloads

@das-g, @njordan-hsr please review.