Refactor Dewar service methods and improve field handling

Updated Dewar API methods to use protected endpoints for enhanced security and consistency. Added `pgroups` handling in various frontend components and modified the LogisticsView contact field for clarity. Simplified backend router imports for better readability.

backend/tests/test_auth.py

@@ -35,5 +35,5 @@ def test_protected_route():
     assert response.status_code == 200
     assert response.json() == {
         "username": "testuser",
-        "pgroups": [20000, 20001, 20002, 20003],
+        "pgroups": ["20000", "20001", "20002", "20003"],
     }