squidclamav: fix warning page delivery.

The page reside on the ipfire not on the clients so only rewrite-url can used.
Add user nobody to group dialout.

Those permissions are required for modem-status.cgi to
communicate with serial modems.
transmission: update to 2.83.
hostname: New package.
net-tools: Don't build hostname.
hostname: Add rootfile.
icinga: Rootfile update.
Merge branch 'master' of ssh://git.ipfire.org/pub/git/ipfire-2.x
core78: add more changed files to updater.