Add a log option to fetch logs indefinitely

[cjelger]

It would be nice to have an option to fetch the logs "indefinitely", similar to what one can do with tail -f on some local log file.

So something like aio app:logs -f that would output all the logs indefinitely and would never return, except if you hit ctrl + c.

This would be very useful, because developers spend most of their time deploying code, checking the logs, deploying again, etc etc, so it would allow a developer to keep a "logs" terminal/console open in a separate window and get all the logs in almost real-time.

[moritzraho]

Thanks @cjelger!

This somehow relates to #81 and there likely will be some common parts.