Drupal example custom fees

Adds a fee when order includes a custom manual method with id cod. Need to be created seperately. Can be used as an alternative for the yet to be released Drupal 8 commerce_fee module. When https://www.drupal.org/project/commerce_fee is fully supported this might be obsolete but serves also as an example on how to add custom line items to orders.

references

• Drupal commerce fee (in progress)
• Commerce fee related issue
• Idea for bulding a custom solution
• Drupal commerce orders api documentation