Better containerRuntimeExecutor default

[pedro-mandeville]

Summary

Change the default executor to one that works out of the box on more k8s distribution

It seems docker is not a good default as it does not work on every k8s distribution, for example, GKE and microk8s.
Thus a lot of new users trying Argo-Workflow have trouble figuring out why the hello-word example does not work (the wait container get stuck).
As en example, I joined the argo slack channel yesterday and in less than 24 hours there were 3 questions regarding this exactly same issue.

The documentation also does not tells that Argo-Workflow may not work out of the box depending on your k8s distribution. Neither how you can fix it.

---

Message from the maintainers:

Impacted by this bug? Give it a 👍. We prioritise the issues with the most 👍.

[alexec]

I agree with this, more generally deprecating the Docker executor, and defaulting to either the PNS or Emissary executor. The latter is designed to be faster and more powerful, but is new (introduced in v3.1), so not proven yet. I think we could make it the default in v3.3.

Would you be interested in making the code changes?

[pedro-mandeville]

I'm not sure were to make the changes but if there is no one else available, with some guide I can prepare a PR

[terrytangyuan]

+1 to PNS or emissary. Though if we want to make emissary the default, we may need to check all the examples to see if the commands are explicitly specified.