This adds a ksysguard process plugin that provides information about
how much data is being used by a certain process. Since there is no
unpriviledged API available (yet?) for this information, a small
helper application is used that uses libpcap to capture packet sizes,
which is then mapped to individual processes by comparing sockets to
entries in /proc.
The helper application is intentionally kept small and should not
require anything else than cap_net_raw.
Depends on D23287