feat: disable tracking service by default

templates/gitlab-ci-python.yml

@@ -234,10 +234,7 @@ workflow:
     - when: on_success
 
 variables:
-  # variabilized tracking image
-  TBC_TRACKING_IMAGE: "registry.gitlab.com/to-be-continuous/tools/tracking:master"
-
-  # PYTHON_IMAGE: "registry.hub.docker.com/library/python:3"
+  # Default Docker image (can be overridden)
   PYTHON_IMAGE: $[[ inputs.image ]]
   # Default Python project root directory
   PYTHON_PROJECT_DIR: $[[ inputs.project-dir ]]