[SAC] trac.osgeo.org DocumentRoot changed

[Sandro Santilli]

After finding that https://trac.osgeo.org/featureserver was responding
with the full trac environment for the old trac instance I decided to
move the DocumentRoot of trac.osgeo.org down one directory, so to
have a more restricted environment for static documents.

Ideally the instances would be moved to live elsewhere (a good
candidate would be /osgeo/trac/env or similar) but for now, not
knowing what could be referencing the current paths I didn't do
that.

The new docroot, /var/www/trac/html, has now its own local git
repository. We are having a good amount of such repos now, time
to "centralize" them a bit ?

--strk;