I used the existing anchors generated by Docbook, so the anchor part
should be a no-op. This could be useful depending on the
infrastructure we choose to use, and it is better to be explicit than
rely on Docbook's id generating algorithms.
I got rid of the metadata segments of the Markdown files, because they
are outdated, inaccurate, and could make people less willing to change
them without speaking with the author.
Reorganize the chapters into parts and reduce the TOC depth to make the
TOC useful again. The top-level TOC is very brief, but that is fine
because every part will have its own TOC.
Section titles of languages/frameworks are also simplified to just
the name of the language/framework.
