Consistent console_log() API

Depending on the cloud, calling `console_log()` can return str, bytes, None, Result (from subp), or raise NotImplementedError. Additionally, often time when returning a str, the text is something along the lines of "No Console Output" if no console output is found. We should ensure these methods have a consistent return type, that None/exceptions represent the same thing across all clouds, and some indication of whether we expected to have text in the console log or not. If would be preferrable to rely on typing/exceptions rather than checking for 'No Console Output'.