Rewrite and expand the Configuration wiki page

The current page has multiple issues:

1. It doesn't contain enough anchors, so linking to a single section or setting is impossible. Obviously, the anchors that are already there should be retained in some form, so that old links work reasonably well.

2. It contains some information that is perhaps better suited for the “FAQ” page or the “Getting Started” page. At the very least, they should be interlinked better.

3. The formatting is inconsistent and just generally not very readable.

4. There aren't a lot of examples, and the acceptable values aren't really shown that well, if at all.