Helm3 apps and guestbook support

[Talador12]

The examples were great for previous versions of helm, but there needs to be a helm3 version of apps and of helm-guestbook. I recommend leaving the older version of those two folders, but creating new helm3 versions in new folders so a simple command change can fix the issue. Currently argo has no docs for a helm3 app of apps pattern, which is now the standard way to use helm.

[agaudreault]

Closing since examples are Helm v3