Add matrix_skip_setup_server_base variable to skip server_base setup

roles/matrix-base/tasks/main.yml

@@ -13,7 +13,9 @@
     - setup-all
 
 - import_tasks: "{{ role_path }}/tasks/server_base/setup.yml"
-  when: run_setup|bool
+  when:
+    - run_setup|bool
+    - not matrix_skip_setup_server_base|bool
   tags:
     - setup-all