Add transaction blocks

This adds transaction queue functionality to the SQLConnectionHandler. There is the ability to have multiple queues per connection handler, as well as the ability to use returned values from a previous sql query in subsequent queries in the queue.
Queues are created using the `create_queue` method and then added to using the `add_to_queue` method. Calling `execute_queue` executes the queue, as expected.
To use previous result values, you need to know the order a previous query returns in. Then, you can use a similar format to the string format function to insert these values. The tests added give a good example of this functionality.
We would lose the ability to pass things down from one SQL command to another, but it would be way easier on our end from a programming point of view. We may just want to replace psycopg2 completely with this though, as it seems to just be naturally async.