Feature: Renting manager role

[Ellen-Wittingen]

Added a role for renting managers with which they have the following permissions:

• Activities
  • See a list of all activities, also the ones that are locked
  • Create, edit, and delete activities
  • View an activity, including the tabs "Samenvatting", "Bestellingen", and "Producttotalen"
  • Access the order screen and place orders with it, but credit mutations (Geld inleggen)
• Invoices
  • See a list of all invoices
  • View an invoice, but not edit or send it
• Pricelists
  • See a list of all unarchived pricelists and the prices for each product, but not edit
• Users
  • See a list of all manually added users, but not from AMBER except for themselves
  • View a manually added user and their credit, orders, and credit mutations

The following permissions were changed for main bartenders (after talking to Soccie):

• Activities: In the activity view, only the tabs "Samenvatting" and "Producttotalen" can be viewed now.

I also added tests for the new renting-manager role and added some tests that were missing for some controllers. The syntax used is a bit inconsistent across tests (also in the already existing tests), I will fix this in some another pull request in the future.

To easily log in as the different roles, I added new users to the seeding of AMBER-API which are linked to SOFIA roles in the seeding of SOFIA, see #412

[lodewiges]

What does this mean?
and why is the change needed?