It never made sense to keep these documents together; move each into its
own file.
Drop the section numbering on hsi.txt on its way to its own file.
Suggested-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
We don't need to keep it as a single large file anymore; split it up so
that it is easier to manage and the individual sections can be read
directly as plain files.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>