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

tasks/hostname_validation.yaml

@@ -2,7 +2,7 @@
 
 - name: Set default hostname
   ansible.builtin.set_fact:
-    lxc_hostname: "new-lxc-test"
+    guest_hostname: "new-lxc-test"
 
 - name: Prompt for hostname with immediate validation
   ansible.builtin.pause:
@@ -19,5 +19,5 @@
 
 - name: Use user input only if provided, otherwise keep the default
   ansible.builtin.set_fact:
-    lxc_hostname: "{{ hostname_result.user_input }}"
+    guest_hostname: "{{ hostname_result.user_input }}"
   when: hostname_result.user_input | length > 0