Add ping probe support

Use liboping (new dependency) to add 'ping XXX' entries support in .cfg
file, where XXX can be either IP address or FQDN.

Sample output:
...
  ping
    ya.ru
      IP: 2a02:6b8::2:242
      dropped: 3/3
    8.8.8.8
      IP: 8.8.8.8
      dropped: 0/3
      latency: 20.4 ms
      TTL: 120
...

N. B: to gather actual ping statistic we have to be able to send ICMP
requests (have enough privileges to work with RAW sockets).

Related: SYS#2655
Change-Id: Ife32540b532fb54368f63c78fb7837b84d4e8c76
5 files changed