Reintroduce default database config

InvenTree/config_template.yaml

@@ -10,6 +10,11 @@ database:
   # Uncomment (and edit) one of the database configurations below,
   # or specify database options using environment variables
   
+  # Default installation uses a simple sqlite database
+  # For production, consider changing this!
+  ENGINE: sqlite3
+  NAME: '/home/inventree/database.sqlite3'
+
   # Refer to the django documentation for full list of options
   
   # --- Available options: ---