This moves lots of pages around. The high-level changes are
* Better main sections, so it's more *general*, *into*, *basics* and *details*
* Move more general topics to a *Basic* section, which are not
app-specific
* Remove app docs to the stuff that is likely used, anything else goes
into "Digging deeper"
* Move general guides into a prologue
* Try to *compress*/combine some pages with similar content
* Try to have better consistencs on level ob abstraction across pages
* Split app development and maintenance pages into two sections
* Integrate bugtracker info into prologue
* Integrate Android pages into client APIs section
Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>
