Follow-on work to PR 590 (integration testing)

[Charles Stern]

In the interest of keeping #590 as narrowly-scoped as possible, the following items did not get completed as part of that PR, but are all important parts of the integration testing story, which I/we should address shortly:

• After #608 is complete, un-xfail the kerchunk test.
• Debug failing narr_opendap and terraclimate recipes; un-xfail them once they work. The latter of these two might just be a timeout issue.
• Integration test against Deploy Recipe Action as well.
• Have pangeo-forge-runner integration tests point at the examples directory here.
• Developer docs for how these tests work
• Provide and all install option that includes pangeo-forge-runner

Originally posted by @cisaacstern in #590 (comment)