Remove hard-coded CPU ID 0 appended to RTE workers

[roland-sipos]

dpdklibs/plugins/DPDKReaderModule.cpp

Line 148 in a78a6d8

rte_cores.push_back(0);

Primary LCore can be controlled through EAL variables, we should rely on that.
For the GARP sender, one should use an RTE_worker thread, instead of an std::thread (which will run on the primary CPU core).