Refactor: remove legacy update-docker role and references

Details:
- Removed update-docker role (README, meta, vars, tasks, script)
- Cleaned references from group_vars, update-compose, and docs
- Adjusted web-app-matrix role (removed @todo pointing to update-docker)
- Updated administrator guide (update-docker no longer mentioned)

Ref: https://chatgpt.com/share/68bbeff1-27a0-800f-bef3-03ab597595fd

roles/update-compose/tasks/01_core.yml

@@ -14,13 +14,6 @@
     name: update-apt
   when: ansible_distribution == "Debian"
 
-- name: "Update Docker Images"
-  include_role:
-    name: update-docker
-  when:
-    - docker_compose_directory_stat.stat.exists
-    - run_once_update_docker is not defined
-
 - name: "Check if yay is installed"
   command: which yay
   register: yay_installed