feat(pb,role,task): generalize names of common pre_tasks and their variables, specifies LXC-specific ones

tasks/human_admin_user_validation.yaml

@@ -2,7 +2,7 @@
 
 - name: Set default human admin user
   ansible.builtin.set_fact:
-    lxc_human_admin_user: true
+    create_human_admin_user: true
 
 - name: Prompt for human admin user creation with immediate validation
   ansible.builtin.pause:
@@ -18,5 +18,5 @@
 
 - name: Use user input only if provided, otherwise keep the default
   ansible.builtin.set_fact:
-    lxc_human_admin_user: "{{ human_admin_user_result.user_input }}"
+    create_human_admin_user: "{{ human_admin_user_result.user_input }}"
   when: human_admin_user_result.user_input | length > 0