Add Daemon Mode

[ashcrow]

Feature Request

Create a daemon mode for afterburn for clouds where having a reactive/scheduled pattern makes sense instead of oneshot runs.

Environment

TBD

Desired Feature

Allow specific providers to have a daemon mode which runs consistently and reacts to specific changes.

Other Information

@darkmuggle has done some initial plumbing work.

[lucab]

This is a quite big architectural change, which for the moment we are not undertaking.

The main rationale is that we are on purpose not trying to re-implement an omni-cloud all-encompassing daemon agent, but instead breaking apart common functionality in single one-short verbs.

If we ever start doing down that route, there are a few pre-requirements to address first, like #252.

[bgilbert]

This is still not currently planned, so I'll close this out for now.