Add support for alternate databases in the trigger.acl.queue.Queue library

The task queue is tedious and broken. Let's make it easier to use and extensible!

There is a great single-file pure Python ORM called [Peewee](https://github.com/coleifer/peewee) that I think would be a good way to add support for other DBs like SQLite and PostgreSQL without having to write SQL. Yes!