Allow iteration of configuration sections.
Now that sections have been added in CONFOUND-22, it would be handy to be able to iterate over them; something like this:
One issue that needs to be decided on: how does iteration work with fallback? If this configuration has a "foo" section and its parent has both a "foo" and a "bar" section, does this configuration return both "foo" and "bar" sections? (Probably.) Does the "foo" section include elements from the fallback "foo" section? (Probably not, because we are considering sections as independent entities when retrieved by themselves.