Review `time_resolution_init()`

[AltraMayor]

Function time_resolution_init() located in file main/main.c estimates the frequency of the TSC register and sets its result in a couple global variable in different units (e.g. cycles_per_sec). DPDK has function rte_get_tsc_hz(), which is equivalent to the global variable cycles_per_sec.

Which function is more precise, time_resolution_init() or rte_get_tsc_hz()? If time_resolution_init(), we should submit a patch to DPDK. In any case, we should adopt rte_get_tsc_hz() in time_resolution_init() to simplify our code.

We should also investigate if the global variables are still needed. For example, should we replace variable cycles_per_sec with rte_get_tsc_hz() or keep it?