Compatibility layer for `background_task`

[tcely]

It looks like it will be possible to create a background decorator that translates to the Huey task system.

• [x] Modify TaskWrapper
• [x] Alias now to call_local
• [x] Customize the get_task_wrapper_class function
• [x] Handle all the args accepted by background

• • [x] name
• • [x] schedule
• • [x] queue
• • [x] remove_existing_tasks

• [x] Handle all the kwargs accepted by TaskProxy

• • [x] schedule
• • [x] priority
• • [x] queue
• • [x] verbose_name
• • [x] creator
• • [x] repeat
• • [x] repeat_until
• • [x] remove_existing_tasks

• [x] Investigate possibly using TaskWrapper.task_base