Support feature worker declaration from gitlab.teklia.com

Closes #1883 (closed)

• Requires tests

arkindex/process/tests/commands/test_update_system_workers.py

@@ -671,7 +671,7 @@ class TestUpdateSystemWorkers(ArkindexTestCase):
             Current worker version: {init_elements_version.id} (registry.gitlab.teklia.com/callico/callico:latest)
             This version has an invalid Docker image.
             This version uses a custom Docker command which could interfere with the feature.
-            This version requires a custom worker configuration which could interfere with the feature.
+            This version uses a custom configuration which could interfere with the feature.
             Unassigning feature from the current version
             Worker is up to date
             Creating new worker version