Unit test cases for the instrument controller

• Unit test cases for the instrument controller
  • Set node_env to test for the test variant (blubber file)
• route, controller and service layers have been refactored for better project organization and to allow unit testing
• Sanitization and validation have been added when getting an instrument (GET /instrument/:slug)
• actionLogger util library (salUtil so far) has been created to refactor and add a kind of abstraction layer to log actions (SAL was implemented but there is an open discussion to replace it with a different mechanism)
• A couple of changes to adapt the frontend to the new responses (same structure for ok and ko responses)

Note: after pushing the last change to this MR, the pipeline is working fine with all these new unit test cases

Bug: T367853