Add and document some strategies around time-constrained experiments

[russmiles]

Original content from docs: # Adding Time Constraints to an Experiment

It is a common requirement to execute a chaos experiment for a certain period of time, ending the experiment if it goes on indefinitely.

We've been very careful to rely on other tools for these types of concerns, and so timing constraints are not a built-in feature of the Chaos Toolkit's experiments.

[russmiles]

The original request, for documentation around this, is here: https://github.com/chaostoolkit/chaostoolkit-documentation/issues/25

[Lawouach]

I'm torn about this one. Much like you said @russmiles, we've avoided to include too much concerns into the core of the toolkit (say for instance like scheduling).

What could be created however is a plugin registered on hook points, that plugin could create such a supervisor.

[russmiles]

I like the idea of a plugin for this, it does feel like an extension of that sort. Or possibly a wrapper for the toolkit's CLI itself, with the wrapper being supervisory?

[russmiles]

Documented, and catered for by external tools for now.