Added filter which calculates the traffic for a host
Added filter which calculates the traffic for a host

I added this filter to use the traffic preview for a specific host in the
user overview.

lukasjuhrich/pycroft,agdsn/pycroft,agdsn/pycroft,agdsn/pycroft,agdsn/pycroft,agdsn/pycroft,lukasjuhrich/pycroft,lukasjuhrich/pycroft,lukasjuhrich/pycroft