Better generated configuration docs.

* Generates docs from more settings classes.
* Extracts information on valid values, deprecated or mandatory settings and default values.
* Makes every setting easy to link to.
* Uses new annotations @Internal and @Obsoleted to add information to settings.
* Cleans up language and formatting in settings descriptions.
* Upgrade of doctools, including moving to a JVM-based DocBook validation and better support for mobile devices.
It might still be supported, but shouldn't look like that anymore. It was changed here: https://github.com/neo4j/neo4j/commit/b8d7ae9ab610637cf10e981220f267e2d3eb212e