Add firefox policies for Linux, merge them with windows

roles/firefox/tasks/main_lin.yml

@@ -31,3 +31,13 @@
       - firefox
     state: latest
     allow_downgrade: True
+
+- name: Create Firefox policies directory
+  file:
+    path: /etc/firefox/policies
+    state: directory
+
+- name: Set Firefox policies
+  copy:
+    dest: /etc/firefox/policies/policies.json
+    src: policies.json