docs: really move the website

Now that the automated scripts that deply our website have been updated,
really move the website to its final location.

We still keep a symlink for the images, as they are used both for the
website, and for the manual.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Peter Korsgaard <jacmet@uclibc.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>