refactor(bootstrap): restructure package lists to self-contained per-OS dicts with base/extra/conditional

roles/bootstrap/tasks/archlinux.yml

@@ -1,11 +1,14 @@
 ---
 - name: Bootstrap ArchLinux
   vars:
+    _config: "{{ lookup('vars', bootstrap_var_key) }}"
     bootstrap_archlinux_packages: >-
       {{
-        lookup('vars', bootstrap_var_key)
+        ((_config.base | default([])) + (_config.conditional | default([])))
+        | reject('equalto', '')
+        | list
       }}
   ansible.builtin.command: >-
-    pacstrap /mnt {{ bootstrap_archlinux_packages | reject('equalto', '') | join(' ') }} --asexplicit
+    pacstrap /mnt {{ bootstrap_archlinux_packages | join(' ') }} --asexplicit
   register: bootstrap_result
   changed_when: bootstrap_result.rc == 0