Draft: Resolve "backup all installed apps and system"

Closes #25 (closed)

defaults/main.yml

@@ -63,3 +63,11 @@ ynh_apps: null
   #       owner: ttrss # Only provide if different from app name
   #       group: ttrss # Only provide if different from www-data
 
+# Variables for backup
+ynh_apps_backup:
+  scheduled: "false"
+  # directory: "/data/backup"
+  # scheduled_hour: 3
+  # scheduled_minute: "0"
+  # scheduled_weekday: "*"
+  # scheduled_month: "*"