add flatpak option for firefox

tasks/pkgs/firefox.yml

@@ -1,11 +1,21 @@
 # vim: set filetype=yaml.ansible :
 ---
+- name: Load firefox config
+  ansible.builtin.include_tasks:
+    file: config/firefox.yml
+
 - name: Append firefox to pkg_sys
   when:
-    - ansible_system == 'Linux'
+    - firefox.method == 'sys'
   ansible.builtin.set_fact:
     pkg_sys: "{{ pkg_sys + ['firefox'] }}"
 
+- name: Install firefox as flatpak
+  when:
+    - firefox.method == 'flatpak'
+  ansible.builtin.set_fact:
+    pkg_flatpak: "{{ pkg_sys + ['org.mozilla.firefox'] }}"
+
 - name: Append firefox to pkg_cask
   when:
     - ansible_system == 'Darwin'