refactor(partitioning): move btrfs home quota to configurable default

roles/partitioning/tasks/btrfs.yml

@@ -60,7 +60,7 @@
       when: system_cfg.features.cis.enabled
       ansible.builtin.command: btrfs qgroup limit {{ item.quota }} /mnt/{{ '@' if item.subvol == 'root' else '@' + item.subvol }}
       loop:
-        - { subvol: home, quota: 2G }
+        - { subvol: home, quota: "{{ partitioning_btrfs_home_quota }}" }
       register: partitioning_btrfs_qgroup_result
       changed_when: false