Read and parse configuration files. Fixes#41.
* supports nDPId / nDPIsrvd via command line parameter `-f`
* nDPId: read general/tuning and libnDPI settings
* support for settings risk domains libnDPI option via config file or via `-R` (Fixes#45, thanks to @UnveilTech)
* added some documentation in the config file
* adjusted Systemd and Debian packaging to make use of config files
Signed-off-by: Toni Uhlig <matzeton@googlemail.com>
