legal-info: Add site to legal info manifest

I would like to propose adding the site to the legal-info manifest
files. This gives a little more information on where the sources came
from without adding much overhead. Please note that is is only for
packages where the source is not local or set with OVERRIDE_SRCDIR.

Signed-off-by: Clayton Shotwell <clayton.shotwell@rockwellcollins.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>