Sylvia/docs/ora 65

@mhoeber @lamagnifica @stephensanchez @wedaly @gradyward Please review. This is a draft so things may be a little rough around the edges, and I have a couple of notes to myself inline.
Good suggestion re: beta testing xref.

I decided not to format it as a list because all of the other steps are really specific, whereas here we're just giving a general idea of what to do. A step-by-step list would feel clunky here. But I admit it's entirely a matter of personal preference, and probably not particularly consistent. :-)