Consistent approach to 'wait' methods

We have a number of wait methods including
wait, wait_for_execute, wait_for_cloudinit, wait_for_delete, wait_for_stop, ...

Most of these wait for some arbitrary amount of time and retry and different wait intervals. We should refactor all of these methods to take an optional timeout argument with a consistent default and a consistent retry interval.

Personally, I'd consider [the retry library](https://pypi.org/project/retry/) or an API that looks like it.