move release date and version to global config file

and display version in download button on first page

Signed-off-by: Sven Nierlein <sven@nierlein.de>
docs: changed title

to make it different that the developer docs title

Signed-off-by: Sven Nierlein <sven@nierlein.de>
migrated dox documentation into website

Its better to have it all in one place. And even if we want to ship some
documentation later, its still easier to edit all in one place and just
export the docs into the tarball.

Signed-off-by: Sven Nierlein <sven@nierlein.de>