nginx: Reduce access log content for static data

For proxy/fastcgi/uwsgi blocks, logging is still set to the old format,
but for everything else (= static data) a reduced format is used that
excludes items that no longer make sense (request_time, remote_user) and
those that are personal information all the time (remote_addr, http_x_forwarded_for).

Signed-off-by: Florian Pritz <bluewind@xinu.at>